{"id":181,"date":"2009-03-24T03:56:19","date_gmt":"2005-04-08T02:35:53","guid":{"rendered":"http:\/\/vafs.dungnq.local\/2005\/04\/08\/moi-quan-he-giua-nguon-nuoc-va-cac-kieu-rung-nhiet-doi-gio-mua-trong-khu-vuc-ven-bien-dong-nam-bo-viet-nam\/"},"modified":"2019-09-25T09:49:35","modified_gmt":"2019-09-25T02:49:35","slug":"moi-quan-he-giua-nguon-nuoc-va-cac-kieu-rung-nhiet-doi-gio-mua-trong-khu-vuc-ven-bien-dong-nam-bo-viet-nam","status":"publish","type":"post","link":"https:\/\/vafs.gov.vn\/vn\/moi-quan-he-giua-nguon-nuoc-va-cac-kieu-rung-nhiet-doi-gio-mua-trong-khu-vuc-ven-bien-dong-nam-bo-viet-nam\/","title":{"rendered":"M\u1ed0I QUAN H\u1ec6 GI\u1eeeA NGU\u1ed2N N\u01af\u1edaC V\u00c0 C\u00c1C KI\u1ec2U R\u1eeaNG NHI\u1ec6T \u0110\u1edaI GI\u00d3 M\u00d9A TRONG KHU V\u1ef0C VEN BI\u1ec2N \u0110\u00d4NG NAM B\u1ed8 (VI\u1ec6T NAM)"},"content":{"rendered":"

Tr\u01b0\u01a1ng Quang T\u00e2m <\/em><\/strong><\/p>\n

Vi\u1ec7n Sinh h\u1ecdc Nhi\u1ec7t \u0111\u1edbi, Vi\u1ec7t Nam <\/em><\/h1>\n

D\u01b0\u01a1ng Ti\u1ebfn D\u0169ng <\/em><\/strong><\/p>\n

Tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc Khoa h\u1ecdc T\u1ef1 nhi\u00ean TP H\u1ed3 Ch\u00ed Minh<\/em><\/p>\n

R. Mitloehner<\/em><\/strong><\/p>\n

Vi\u1ec7n Nghi\u00ean C\u1ee9u L\u00e2m nghi\u1ec7p Nhi\u1ec7t \u0111\u1edbi<\/em><\/p>\n

Th\u1ec1m l\u1ee5c \u0111\u1ecba v\u00f9ng \u0110\u00f4ng Nam \u00c1 l\u00e0 khu v\u1ef1c ph\u1ea7n l\u1edbn ch\u1ecbu \u1ea3nh h\u01b0\u1edfng c\u1ee7a kh\u00ed h\u1eadu gi\u00f3 m\u00f9a: m\u00f9a m\u01b0a (k\u00e9o d\u00e0i t\u1eeb th\u00e1ng n\u0103m \u0111\u1ebfn th\u00e1ng m\u01b0\u1eddi) v\u00e0 m\u00f9a kh\u00f4 (t\u1eeb th\u00e1ng m\u01b0\u1eddi m\u1ed9t \u0111\u1ebfn th\u00e1ng t\u01b0 n\u0103m sau). L\u01b0\u1ee3ng m\u01b0a t\u01b0\u01a1ng \u0111\u1ed1i th\u1ea5p, h\u00e0ng n\u0103m kho\u1ea3ng 1000 – 1500mm\/n v\u00e0 5 \u0111\u1ebfn 7 th\u00e1ng kh\u00f4 (Stott 1991) l\u00e0 nh\u1eefng nh\u00e2n t\u1ed1 \u0111em l\u1ea1i s\u1ef1 h\u00ecnh th\u00e0nh c\u00e1c ki\u1ec3u r\u1eebng m\u01b0a nhi\u1ec7t \u0111\u1edbi gi\u00f3 m\u00f9a. C\u00e1c ki\u1ec3u r\u1eebng m\u01b0a th\u01b0\u1eddng xanh v\u00e0 kh\u00f4 n\u00e0y n\u1eb1m t\u1ea1i c\u00e1c khu v\u1ef1c t\u1eeb Li\u00ean bang Manipur, Myanmar, Th\u00e1i Lan, L\u00e0o, Campuchia \u0111\u1ebfn Vi\u1ec7t Nam \u0111\u1ec1u c\u00f3 nhi\u1ec1u \u0111\u1eb7c \u0111i\u1ec3m gi\u1ed1ng nhau. Ch\u00fang \u0111\u01b0\u1ee3c t\u00e1ch ri\u00eang ra kh\u1ecfi khu v\u1ef1c r\u1eebng \u1ea9m th\u01b0\u1eddng xanh, n\u01a1i m\u00e0 l\u01b0\u1ee3ng m\u01b0a h\u00e0ng n\u0103m cao h\u01a1n 2000 mm\/a v\u00e0 kh\u00f4ng c\u00f3 kh\u00f4 h\u1ea1n kh\u1eafc nghi\u1ec7t (Rundel v\u00e0 Boonpragob 1995).<\/p>\n

C\u00e1c ki\u1ec3u r\u1eebng nhi\u1ec7t \u0111\u1edbi gi\u00f3 m\u00f9a trong l\u1ee5c \u0111\u1ecba \u0110\u00f4ng Nam \u00c1 r\u1ea5t \u0111a d\u1ea1ng. C\u00f3 th\u1ec3 v\u00ec v\u1eady m\u00e0 vi\u1ec7c ph\u00e2n lo\u1ea1i c\u1ee7a ch\u00fang, qua c\u00e1c t\u00e0i li\u1ec7u c\u00f4ng b\u1ed1, ch\u01b0a \u0111\u01b0\u1ee3c th\u1ed1ng nh\u1ea5t th\u1eadm ch\u00ed c\u00f2n l\u1ed9n x\u1ed9n n\u1eefa. Hegner (1979) \u0111\u00e3 \u0111\u1ed1i chi\u1ebfu nh\u1eefng ki\u1ec3u r\u1eebng n\u00e0y v\u00e0 nh\u1eefng thu\u1eadt ng\u1eef \u0111\u1ed3ng ngh\u0129a c\u1ee7a ch\u00fang v\u1edbi nhau. Stott (1991) \u0111\u00e3 r\u1ea5t ti\u1ebfc r\u1eb1ng c\u00e1c c\u00f4ng tr\u00ecnh nghi\u00ean c\u1ee9u v\u1ec1 nh\u1eefng ki\u1ec3u r\u1eebng n\u00e0y c\u00f2n r\u1ea5t hi\u1ebfm hoi. Trong khi \u0111\u00f3 c\u00e1c ki\u1ec3u r\u1eebng m\u01b0a nhi\u1ec7t \u0111\u1edbi t\u1ea1i Th\u00e1i Lan \u0111\u00e3 \u0111\u01b0\u1ee3c Bunyavejchewin (1983), Rundel v\u00e0 Boonpragob (1995) v\u00e0 Khamyong v\u1edbi c\u1ed9ng t\u00e1c vi\u00ean. (1983) v\u00e0 t\u1ea1i Vi\u1ec7t Nam g\u1ea7n \u0111\u00e2y c\u00f3 Linh (1996) nghi\u00ean c\u1ee9u. \u0110i\u1ec3m \u0111\u00e1ng ch\u00fa \u00fd trong v\u00f9ng ch\u1ecbu \u1ea3nh h\u01b0\u1edfng c\u1ee7a gi\u00f3 m\u00f9a l\u00e0: ho\u1eb7c ch\u1ec9 m\u1ed9t lo\u00e0i c\u00e2y ho\u1eb7c\/v\u00e0 m\u1ed9t chi (Genus) trong c\u00f9ng m\u1ed9t h\u1ecd s\u1ebd chi\u1ebfm \u01b0u th\u1ebf. \u0110i\u1ec1u n\u00e0y b\u1ed9c l\u1ed9 r\u00f5 nh\u1ea5t \u0111\u1ed1i v\u1edbi h\u1ecd Sao D\u1ea7u (Dipterocarpaceae)<\/em> (xem T. Smitinand v\u00e0 ctv. 1990).<\/p>\n

Th\u00eam m\u1ed9t \u0111\u1eb7c \u0111i\u1ec3m chung quan tr\u1ecdng kh\u00e1c n\u1eefa l\u00e0 s\u1ef1 hi\u1ec7n di\u1ec7n s\u00e1t c\u00e1nh nhau c\u1ee7a nhi\u1ec1u ki\u1ec3u r\u1eebng nhi\u1ec7t \u0111\u1edbi gi\u00f3 m\u00f9a tr\u00ean m\u1ed9t di\u1ec7n t\u00edch v\u00f4 c\u00f9ng b\u00e9 nh\u1ecf (Bunyavejchewin 1983; Whithmore 1984; Rudel v\u00e0 Boongrapob 1995). Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y \u0111\u00f4i khi \u0111\u01b0\u1ee3c gi\u1ea3i th\u00edch nh\u01b0 l\u00e0 h\u1ec7 qu\u1ea3 bi\u1ebfn th\u1ec3 c\u1ee7a l\u1eadp \u0111\u1ecba tr\u00ean m\u1ed9t di\u1ec7n t\u00edch v\u00f4 c\u00f9ng b\u00e9 nh\u1ecf t\u00f9y theo l\u01b0\u1ee3ng n\u01b0\u1edbc trong \u0111\u1ea5t v\u00e0 t\u00f9y theo t\u00ednh ch\u1ea5t c\u1ee7a \u0111\u1ea5t (Ogawa v\u00e0 ctv 1961).<\/p>\n

Khu v\u1ef1c nghi\u00ean c\u1ee9u c\u1ee7a ch\u00fang t\u00f4i l\u00e0 khu B\u1ea3o t\u1ed3n B\u00ecnh Ch\u00e2u Ph\u01b0\u1edbc B\u1eedu, thu\u1ed9c huy\u1ec7n Xuy\u00ean M\u1ed9c, t\u1ec9nh B\u00e0 R\u1ecba V\u0169ng T\u00e0u. T\u1ea1i \u0111\u00e2y c\u00f2n s\u00f3t l\u1ea1i m\u1ed9t kho\u1ea3nh r\u1eebng \u0111\u01b0\u1ee3c c\u00f4ng nh\u1eadn l\u00e0 Khu B\u1ea3o t\u1ed3n Thi\u00ean nhi\u00ean v\u00e0o n\u0103m 1993. V\u00e0 t\u1ea1i \u0111\u00e2y ch\u00fang t\u00f4i b\u1eaft g\u1eb7p hi\u1ec7n t\u01b0\u1ee3ng nhi\u1ec1u ki\u1ec3u r\u1eebng nhi\u1ec7t \u0111\u1edbi gi\u00f3 m\u00f9a n\u1eb1m s\u00e1t c\u1ea1nh nhau tr\u00ean m\u1ed9t \u0111\u1ecba b\u00e0n r\u1ea5t nh\u1ecf nh\u01b0 \u0111\u00e3 k\u1ec3 tr\u00ean. V\u1ecb tr\u00ed c\u1ee7a khu B\u1ea3o t\u1ed3n n\u00e0y n\u1eb1m gi\u1eefa 100<\/sup>27\u201957\u2019\u2019 v\u00e0 100<\/sup>37\u201946\u2019\u2019 B c\u0169ng nh\u01b0 1070<\/sup>24\u201931\u2019\u2019 v\u00e0 1070<\/sup>36\u201907\u2019\u2019 \u0110. Di\u1ec7n t\u00edch khu b\u1ea3o t\u1ed3n bao g\u1ed3m 11.000ha. L\u01b0\u1ee3ng m\u01b0a b\u00ecnh qu\u00e2n n\u0103m l\u00e0 1356 mm\/a v\u00e0 nhi\u1ec7t \u0111\u1ed9 trung b\u00ecnh n\u0103m kho\u1ea3ng 260<\/sup>C. M\u00f9a kh\u00f4 k\u00e9o d\u00e0i su\u1ed1t 7 th\u00e1ng, t\u1eeb th\u00e1ng 11 \u0111\u1ebfn th\u00e1ng 3 n\u0103m sau. Gi\u00f3 m\u00f9a T\u00e2y nam \u0111em m\u01b0a l\u1ea1i cho khu v\u1ef1c t\u1eeb th\u00e1ng 4 \u0111\u1ebfn th\u00e1ng 10. L\u01b0\u1ee3ng m\u01b0a trong nh\u1eefng th\u00e1ng n\u00e0y chi\u1ebfm 93% t\u1ed5ng l\u01b0\u1ee3ng m\u01b0a su\u1ed1t c\u1ea3 n\u0103m. V\u1ec1 \u0111\u1ea5t, th\u00e0nh ph\u1ea7n c\u1ea5u t\u1ea1o ch\u00ednh l\u00e0 c\u00e1t, kho\u1ea3ng 90%.<\/p>\n

5 ki\u1ec3u r\u1eebng thu\u1ed9c ba qu\u1ea7n th\u1ec3 r\u1eebng \u0111\u00e3 \u0111\u01b0\u1ee3c l\u1ef1a ch\u1ecdn \u0111\u1ec3 nghi\u00ean c\u1ee9u. C\u00e1c \u00f4 r\u1eebng nghi\u00ean c\u1ee9u tr\u1ea3i d\u00e0i tr\u00ean m\u1ed9t \u0111\u01b0\u1eddng c\u1eaft (Transekts) kho\u1ea3ng 6,5 km. Ch\u00fang c\u00f3 chung \u0111i\u1ec1u ki\u1ec7n kh\u00ed h\u1eadu v\u00e0 n\u1ec1n \u0111\u1ea5t, song l\u1ea1i r\u1ea5t kh\u00e1c nhau v\u1ec1 chu k\u1ef3 r\u1ee5ng l\u00e1, v\u1ec1 th\u00e0nh ph\u1ea7n lo\u00e0i v\u00e0 v\u1ec1 c\u1ea5u tr\u00fac. C\u00f9ng v\u1edbi vi\u1ec7c kh\u1ea3o s\u00e1t th\u1ea3m th\u1ef1c v\u1eadt v\u00e0 l\u1ea5y m\u1eabu \u0111\u1ea5t, ch\u00fang t\u00f4i ti\u1ebfn h\u00e0nh nghi\u00ean c\u1ee9u \u0111\u1eb7c t\u00ednh sinh l\u00fd c\u1ee7a c\u00e1c lo\u00e0i \u01b0u th\u1ebf thu\u1ed9c m\u1ed7i ki\u1ec3u r\u1eebng. Ch\u00fang t\u00f4i \u0111o tr\u1ef1c ti\u1ebfp l\u01b0\u1ee3ng n\u01b0\u1edbc ti\u1ec1m t\u00e0ng c\u0169ng nh\u01b0 h\u00e0m l\u01b0\u1ee3ng mu\u1ed1i trong \u0111\u1ea5t th\u00f4ng qua vi\u1ec7c \u0111o \u00e1p su\u1ea5t th\u1ea9m th\u1ea5u c\u1ee7a l\u00e1 n\u01a1i c\u00e1c c\u00e2y \u0111\u01b0\u1ee3c l\u1ef1a ch\u1ecdn. T\u1eeb \u0111\u00f3 ch\u00fang t\u00f4i tr\u1ef1c ti\u1ebfp x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c t\u00e1c \u0111\u1ed9ng c\u1ee7a n\u01b0\u1edbc v\u00e0 mu\u1ed1i c\u1ee7a t\u1eebng l\u1eadp \u0111\u1ecba (xem R. Mitloehner 1997b). Song song v\u1edbi vi\u1ec7c ph\u00e2n t\u00edch nh\u1eefng \u0111i\u1ec1u ki\u1ec7n l\u1eadp \u0111\u1ecba (kh\u00ed h\u1eadu v\u00e0 \u0111\u1ea5t), ch\u00fang t\u00f4i chuy\u00ean ch\u00fa \u00fd nghi\u00ean c\u1ee9u s\u1ef1 th\u00edch \u1ee9ng sinh l\u00fd c\u1ee7a c\u00e2y v\u1edbi \u0111i\u1ec1u ki\u1ec7n l\u1eadp \u0111\u1ecba. C\u00e1c th\u00f4ng s\u1ed1 c\u00f3 \u0111\u01b0\u1ee3c l\u00e0 k\u1ebft qu\u1ea3 \u0111o \u0111\u1ea1c v\u00e0o l\u00fac tr\u01b0a (l\u00fac n\u00f3ng nh\u1ea5t trong ng\u00e0y) v\u00e0 v\u00e0o ban \u0111\u00eam (l\u00fac \u0111\u01b0\u1ee3c xem l\u00e0 m\u00e1t nh\u1ea5t trong ng\u00e0y). Ch\u00fang n\u1eb1m trong m\u1ed1i quan h\u1ec7 gi\u1eefa l\u01b0\u1ee3ng n\u01b0\u1edbc ti\u1ec1m t\u00e0ng trong c\u00e2y (WP) v\u00e0 ti\u1ec1m n\u0103ng th\u1ea9m th\u1ea5u n\u1ed9i t\u1ea1i c\u1ee7a c\u00e2y (OP) (xem R. Mitloehner 1996,1997a). T\u1ea1i v\u00f9ng kh\u00f4 khan \u0111\u1ecbnh k\u1ef3 th\u00ec s\u1ef1 cung \u1ee9ng c\u1ee7a n\u01b0\u1edbc v\u00e0 \u0111\u1ed9 m\u1eb7n l\u00e0 2 y\u1ebfu t\u1ed1 quy\u1ebft \u0111\u1ecbnh cho s\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a th\u1ef1c v\u1eadt. Trong khu\u00f4n kh\u1ed5 c\u1ee7a nghi\u00ean c\u1ee9u n\u00e0y c\u00e1c c\u00e2u h\u1ecfi sau \u0111\u00e2y \u0111\u01b0\u1ee3c \u0111\u1eb7t ra :<\/p>\n

\u00b7 5 ki\u1ec3u r\u1eebng \u0111\u01b0\u1ee3c ch\u1ecdn nghi\u00ean c\u1ee9u kh\u00e1c bi\u1ec7t nhau ra sao \u0111\u1ed1i v\u1edbi nh\u1ecbp m\u00f9a r\u1ee5ng l\u00e1, \u0111\u1ed1i v\u1edbi th\u00e0nh ph\u1ea7n lo\u00e0i v\u00e0 c\u1ea5u tr\u00fac r\u1eebng?<\/p>\n

\u00b7 C\u00e1c y\u1ebfu t\u1ed1 l\u1eadp \u0111\u1ecba n\u00e0o c\u00f3 th\u1ec3 t\u1ea1o ra s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa c\u00e1c ki\u1ec3u r\u1eebng ?<\/p>\n

\u00b7 C\u00f3 th\u1ec3 th\u00f4ng qua vi\u1ec7c \u0111o c\u00e1c th\u00f4ng s\u1ed1 sinh l\u00fd c\u1ee7a c\u00e2y \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh h\u00e0m l\u01b0\u1ee3ng n\u01b0\u1edbc v\u00e0 kh\u1ea3 n\u0103ng th\u00edch \u1ee9ng v\u1ec1 m\u1eb7t th\u1ea9m th\u1ea5u c\u1ee7a ch\u00fang c\u0169ng nh\u01b0 \u0111\u1ec3 c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c nh\u1eefng bi\u1ebfn th\u1ec3 c\u1ee7a c\u00e1c kho\u1ea3nh r\u1eebng kh\u00f4ng?<\/p>\n

Ph\u01b0\u01a1ng ph\u00e1p lu\u1eadn:<\/strong><\/p>\n

\u0110\u1eb7t \u00f4 m\u1eabu \u0111\u1ec3 m\u00f4 t\u1ea3 c\u1ea5u tr\u00fac r\u1eebng <\/em><\/h3>\n

Tr\u01b0\u1edbc h\u1ebft ch\u00fang t\u00f4i ch\u1ecdn 5 ki\u1ec3u r\u1eebng kh\u00e1c nhau, b\u1ed1 tr\u00ed cho m\u1ed7i ki\u1ec3u m\u1ed9t \u00f4 ti\u00eau chu\u1ea9n v\u1edbi k\u00edch th\u01b0\u1edbc 50 x 50 m. Sau \u0111\u00f3, ti\u1ebfn h\u00e0nh \u0111o, \u0111\u1ebfm t\u1ea5t c\u1ea3 c\u00e1c c\u00e2y trong \u00f4 c\u00f3 \u0111\u01b0\u1eddng k\u00ednh ngang vai (dBH) tr\u00ean 10 cm, x\u00e1c \u0111\u1ecbnh t\u00ean, v\u1ecb tr\u00ed, chi\u1ec1u cao to\u00e0n th\u00e2n, chi\u1ec1u cao d\u01b0\u1edbi t\u00e1n c\u1ee7a t\u1eebng c\u00e2y…<\/p>\n

\u0110\u01b0\u1eddng k\u00ednh ngang vai \u0111\u01b0\u1ee3c \u0111o b\u1eb1ng th\u01b0\u1edbc \u0111o \u0111\u01b0\u1eddng k\u00ednh (Umfangmessband), chi\u1ec1u cao to\u00e0n th\u00e2n \u0111\u01b0\u1ee3c \u01b0\u1edbc l\u01b0\u1ee3ng theo c\u00e1c l\u1ea7n \u0111o m\u1eabu v\u1edbi d\u1ee5ng c\u1ee5 Blume Leiss v\u00e0 th\u01b0\u1edbc ng\u1eafm Teleskopestange v\u1edbi sai s\u1ed1 1m.<\/p>\n

Nghi\u00ean c\u1ee9u th\u1ed5 nh\u01b0\u1ee1ng<\/em><\/strong><\/p>\n

\u0110\u1ec3 b\u1ea3o \u0111\u1ea3m t\u00ednh ch\u00ednh x\u00e1c v\u00e0 t\u00ednh \u0111\u1ea1i di\u1ec7n, ch\u00fang t\u00f4i \u0111\u00e3 ti\u1ebfn h\u00e0nh ngay t\u1ea1i \u0111\u1ecba \u0111i\u1ec3m trung t\u00e2m c\u1ee7a \u00f4 ti\u00eau chu\u1ea9n c\u00e1c vi\u1ec7c sau \u0111\u00e2y:<\/p>\n

– L\u1ea5y m\u1eabu \u0111\u1ea5t t\u1ea1i hai \u0111\u1ed9 s\u00e2u kh\u00e1c nhau: 10cm v\u00e0 50cm. \u00c1p d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p Scheffer v\u00e0 Schachtschnabel (1984) \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u1ed9 ch\u1eb7t v\u00e0 \u0111\u1ed9 m\u00f9n trong \u0111\u1ea5t,<\/p>\n

– Ti\u1ebfn h\u00e0nh \u0111o kh\u1ea3 n\u0103ng trao \u0111\u1ed5i cation (AKe ) v\u00e0 qu\u00e1 tr\u00ecnh c\u1ed1 \u0111\u1ecbnh cation v\u1edbi dung d\u1ecbch NH4<\/sub>CL k\u1ebft h\u1ee3p v\u1edbi vi\u1ec7c \u0111o \u0111\u1ed9 h\u1ea5p th\u1ee5 quang ph\u1ed5 \u00e1nh s\u00e1ng (AAS) theo ph\u01b0\u01a1ng ph\u00e1p c\u1ee7a Ulrich (1966). Th\u00e0nh ph\u1ea7n Nh\u00f4m (Al) \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1eb1ng ph\u00e9p \u0111o tr\u1eafc quang. Tr\u00ean v\u00f9ng \u0111\u1ea5t ven bi\u1ec3n \u00edt nhi\u1ec1u b\u1ecb nhi\u1ec5m m\u1eb7n, tr\u1ecb s\u1ed1 AKe s\u1ebd ph\u1ea3n \u00e1nh nh\u1eefng cation m\u00e0 c\u00e2y c\u00f3 th\u1ec3 h\u1ea5p th\u1ee5 \u0111\u01b0\u1ee3c. Cation n\u00e0y ho\u1eb7c:<\/p>\n

a\/ \u0110\u01b0\u1ee3c c\u1ed1 \u0111\u1ecbnh qua qu\u00e1 tr\u00ecnh trao \u0111\u1ed5i (s\u00e9t, m\u00f9n) ho\u1eb7c<\/p>\n

b\/ \u0110\u01b0\u1ee3c gi\u1ea3i ph\u00f3ng v\u00e0\/ hay bu\u1ed9c ch\u1eb7t trong dung d\u1ecbch \u0111\u1ea5t. Trong tr\u01b0\u1eddng h\u1ee3p \u0111\u1eb7c bi\u1ec7t n\u00e0y tr\u1ecb s\u1ed1 AKe c\u00f3 th\u1ec3 xem nh\u01b0 l\u00e0 m\u1ee9c \u0111\u1ed9 mu\u1ed1i trong \u0111\u1ea5t c\u00f3 th\u1ec3 cung c\u1ea5p cho c\u00e2y trong hi\u1ec7n t\u1ea1i v\u00e0 t\u01b0\u01a1ng lai.<\/p>\n

\u0110o h\u00e0m l\u01b0\u1ee3ng n\u01b0\u1edbc ti\u1ec1m t\u00e0ng trong c\u00e2y (vi\u1ebft t\u1eaft: WP)<\/em><\/strong><\/p>\n

L\u01b0\u1ee3ng n\u01b0\u1edbc ti\u1ec1m t\u00e0ng trong c\u00e2y (= nWP<\/em>) t\u01b0\u01a1ng \u1ee9ng v\u1edbi s\u1ee9c h\u00fat c\u1ee7a c\u00e2y d\u00f9ng \u0111\u1ec3 l\u1ea5y n\u01b0\u1edbc t\u1eeb \u0111\u1ea5t v\u00e0o th\u00e2n c\u1ea7n cho s\u1ef1 ph\u00e1t tri\u1ec3n. Khi l\u00e1 c\u00e2y no n\u01b0\u1edbc, tr\u1ecb s\u1ed1 c\u1ee7a nWP l\u00e0 1 bar. T\u1ea1i nh\u1eefng v\u00f9ng kh\u00f4 h\u1ea1n, tr\u1ecb s\u1ed1 n\u00e0y c\u00f3 th\u1ec3 t\u0103ng \u0111\u1ebfn 80 bar (hay = 800 hPa) (Mitloehner 1990). Gi\u1eefa bu\u1ed5i tr\u01b0a, tr\u1ecb s\u1ed1 n\u00e0y s\u1ebd t\u0103ng \u0111\u1ebfn c\u1ef1c \u0111\u1ea1i, ban \u0111\u00eam s\u1ebd h\u1ea1 xu\u1ed1ng c\u1ef1c ti\u1ec3u v\u00ec l\u00fac \u1ea5y kh\u00ed kh\u1ed5ng \u0111\u00e3 \u0111\u00f3ng k\u00edn v\u00e0 \u0111\u1ed9 \u1ea9m trong kh\u00f4ng kh\u00ed t\u0103ng l\u00ean r\u1ea5t cao. Tr\u1ecb s\u1ed1 \u0111o ban \u0111\u00eam c\u00f3 th\u1ec3 xem nh\u01b0 l\u00e0 l\u1ef1c m\u00e0 \u0111\u1ea5t “k\u00e9o gi\u1eef” l\u1ea1i n\u01b0\u1edbc. Trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y, nh\u1eefng c\u00e2y \u0111\u00e3 \u0111\u01b0\u1ee3c ch\u1ecdn ra \u0111\u1ec3 \u0111o \u0111\u01b0\u1ee3c xem nh\u01b0 l\u00e0 “d\u1ee5ng c\u1ee5 sinh h\u1ecdc” d\u00f9ng \u0111\u1ec3 \u0111o \u00e1p su\u1ea5t (biologischer Tensiometer) (theo Kreeb 1990). Cho m\u1ed7i lo\u00e0i c\u00e2y \u01b0u th\u1ebf trong m\u1ed7i ki\u1ec3u r\u1eebng nghi\u00ean c\u1ee9u, ch\u00fang t\u00f4i \u0111\u00e3 ch\u1ecdn ra 6 c\u00e1 th\u1ec3 l\u00e0m \u0111\u1ed1i t\u01b0\u1ee3ng \u0111o \u0111\u1ea1c v\u00e0o bu\u1ed5i tr\u01b0a v\u00e0 ban \u0111\u00eam v\u1edbi d\u1ee5ng c\u1ee5 chuy\u00ean d\u1ee5ng SCHOLANDER. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y \u0111\u00e3 \u0111\u01b0\u1ee3c Kreeb (1990) c\u0169ng nh\u01b0 Lassoie v\u00e0Hinckley (1991) m\u00f4 t\u1ea3 r\u00f5. Theo c\u00e1c t\u00e1c gi\u1ea3 tr\u00ean th\u00ec sai s\u1ed1 n\u1eb1m \u1edf kho\u1ea3ng 0,1 – 0,2 bar.<\/p>\n

\u0110o kh\u1ea3 n\u0103ng th\u1ea9m th\u1ea5u ti\u1ec1m t\u00e0ng trong c\u00e2y (vi\u1ebft t\u1eaft: OP)<\/em><\/strong><\/p>\n

Ti\u1ec1m n\u0103ng ti\u00eau c\u1ef1c OP trong c\u00e2y (nOP<\/em>) t\u01b0\u01a1ng \u1ee9ng v\u1edbi \u0111\u1ed9 \u0111\u1eadm \u0111\u1eb7c c\u1ee7a mu\u1ed1i, \u0111\u01b0\u1eddng, axid h\u1eefu c\u01a1 v\u00e0 c\u00e1c ch\u1ea5t kh\u00e1c trong t\u1ebf b\u00e0o. Qua ti\u1ec1m n\u0103ng n\u00e0y c\u00e2y ch\u1eb3ng nh\u1eefng c\u00f3 th\u1ec3 h\u1ea5p th\u1ee5 \u0111\u01b0\u1ee3c mu\u1ed1i trong dung d\u1ecbch \u0111\u1ea5t m\u00e0 c\u00f2n c\u00f3 th\u1ec3 t\u1ed5ng h\u1ee3p \u0111\u01b0\u1ee3c \u0111\u01b0\u1eddng v\u00e0 c\u00e1c axid h\u1eefu c\u01a1 trong t\u1ebf b\u00e0o. \u0110i\u1ec1u ki\u1ec7n c\u01a1 b\u1ea3n c\u1ea7n thi\u1ebft cho vi\u1ec7c v\u1eadn chuy\u1ec3n n\u01b0\u1edbc trong qu\u00e1 tr\u00ecnh th\u1ea9m th\u1ea5u l\u00e0 l\u1ef1c OP trong c\u00e2y – hay c\u00f2n g\u1ecdi l\u00e0 \u0111\u1ed9 \u0111\u1eadm \u0111\u1eb7c trong c\u00e2y – \u00edt nh\u1ea5t ph\u1ea3i t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi \u0111\u1ed9 \u0111\u1eadm \u0111\u1eb7c c\u1ee7a dung d\u1ecbch \u0111\u1ea5t. Do \u0111\u00f3 tr\u1ecb s\u1ed1 nPO<\/em> trong c\u00e2y c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 nh\u01b0 l\u00e0 th\u01b0\u1edbc \u0111o s\u1ef1 th\u00edch \u1ee9ng c\u1ee7a c\u00e2y \u0111\u1ed1i v\u1edbi t\u00ecnh tr\u1ea1ng b\u1ea5t thu\u1eadn l\u1ee3i nh\u1ea5t c\u1ee7a h\u00e0m l\u01b0\u1ee3ng mu\u1ed1i t\u1ea1i l\u1eadp \u0111\u1ecba. Nh\u01b0 v\u1eady th\u1ef1c v\u1eadt ph\u1ea3n \u00e1nh \u0111\u01b0\u1ee3c “\u0111\u1ed9 m\u1eb7n” c\u1ee7a th\u1ef1c \u0111\u1ecba.<\/p>\n

V\u00e0o bu\u1ed5i tr\u01b0a, khi m\u00e0 l\u01b0\u1ee3ng n\u01b0\u1edbc trong l\u00e1 gi\u1ea3m \u0111i th\u00ec tr\u1ecb s\u1ed1 nPO<\/em> s\u1ebd l\u00ean \u0111\u1ebfn c\u1ef1c \u0111\u1ea1i, ng\u01b0\u1ee3c l\u1ea1i v\u00e0o ban \u0111\u00eam, khi l\u00e1 no n\u01b0\u1edbc tr\u1edf l\u1ea1i th\u00ec tr\u1ecb s\u1ed1 h\u1ea1 xu\u1ed1ng c\u1ef1c ti\u1ec3u. Ngo\u00e0i ra, \u0111\u1ec3 c\u00f3 th\u1ec3 c\u00f3 nh\u1eefng tr\u1ecb s\u1ed1 t\u01b0\u01a1ng \u0111\u1ed3ng v\u1edbi t\u00ecnh tr\u1ea1ng th\u1ea9m th\u1ea5u c\u1ee7a t\u1eebng lo\u00e0i c\u00e2y t\u01b0\u01a1ng \u1ee9ng, ta c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c tr\u1ecb s\u1ed1 nPO<\/em> c\u1ef1c ti\u1ec3u (nPOsat<\/em>) qua th\u00ed nghi\u1ec7m l\u00e0m no n\u01b0\u1edbc nh\u00e2n t\u1ea1o n\u01a1i c\u00e1c c\u00e2y l\u1ea5y m\u1eabu.<\/p>\n

V\u00e0o bu\u1ed5i tr\u01b0a v\u00e0 ban \u0111\u00eam tr\u01b0\u1edbc l\u00fac m\u1eb7t tr\u1eddi m\u1ecdc, ch\u00fang t\u00f4i \u0111\u00e3 l\u1ea5y m\u1eabu l\u00e1 c\u1ee7a 6 c\u00e2y cho m\u1ed7i lo\u00e0i thu\u1ed9c m\u1ed7i ki\u1ec3u r\u1eebng \u0111\u00e3 l\u1ef1a ch\u1ecdn. L\u00e1 t\u01b0\u01a1i \u0111\u01b0\u1ee3c \u0111o ngay t\u1ea1i hi\u1ec7n tr\u01b0\u1eddng nghi\u00ean c\u1ee9u, r\u1ed3i \u0111\u01b0\u1ee3c s\u1ea5y kh\u00f4 v\u00e0 \u0111\u00f3ng g\u00f3i b\u1ea3o qu\u1ea3n t\u1ee9c kh\u1eafc h\u1ea7u tr\u00e1nh s\u1ef1 bi\u1ebfn \u0111\u1ed5i c\u1ee7a c\u00e1c enzym. Sau \u0111\u00f3, t\u1ea1i ph\u00f2ng th\u00ed nghi\u1ec7m, ch\u00fang t\u00f4i \u1ee9ng d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p \u0111\u00f4ng l\u1ea1nh \u0111\u1ec3 \u0111o n\u1ed3ng \u0111\u1ed9 nh\u01b0 Kreeb (1990) \u0111\u00e3 m\u00f4 t\u1ea3. Theo t\u00e1c gi\u1ea3 n\u00e0y th\u00ec sai s\u1ed1 n\u1eb1m kho\u1ea3ng 2 bar.<\/p>\n

K\u1ebft qu\u1ea3<\/h2>\n

C\u1ea5u tr\u00fac r\u1eebng <\/em><\/h3>\n

Ch\u00fang t\u00f4i ch\u1ecdn 5 ki\u1ec3u r\u1eebng thu\u1ed9c 3 lo\u1ea1i qu\u1ea7n th\u1ec3 r\u1eebng kh\u00e1c nhau \u0111\u1ec3 nghi\u00ean c\u1ee9u. Vi\u1ec7c \u0111\u1eb7t t\u00ean cho ch\u00fang \u0111\u01b0\u1ee3c d\u1ef1a theo Lamprecht(1986) c\u0169ng nh\u01b0 theo t\u00e1n l\u00e1 v\u00e0 chu k\u1ef3 r\u1ee5ng l\u00e1 h\u00e0ng n\u0103m. T\u00ean g\u1ecdi c\u1ee7a m\u1ed7i ki\u1ec3u r\u1eebng \u0111\u1ec1u n\u00f3i l\u00ean th\u00e0nh ph\u1ea7n lo\u00e0i \u0111\u1eb7c tr\u01b0ng trong qu\u1ea7n th\u1ec3. C\u00e1c qu\u1ea7n th\u1ec3 r\u1eebng sau \u0111\u00e2y \u0111\u01b0\u1ee3c ti\u1ebfn h\u00e0nh nghi\u00ean c\u1ee9u :<\/p>\n

a\/ R\u1eebng \u1ea9m th\u01b0\u1eddng xanh, quanh n\u0103m kh\u00f4ng x\u1ea3y ra qu\u00e1 tr\u00ecnh r\u1ee5ng l\u00e1.<\/p>\n

b\/ R\u1eebng m\u01b0a \u1ea9m xanh, v\u00e0o cu\u1ed1i m\u00f9a kh\u00f4 m\u1ed9t s\u1ed1 c\u00e2y thu\u1ed9c t\u1ea7ng cao b\u1eaft \u0111\u1ea7u r\u1ee5ng l\u00e1<\/p>\n

c\/ R\u1eebng kh\u1ed9p, to\u00e0n b\u1ed9 l\u00e1 c\u00e2y r\u1ee5ng v\u00e0o m\u00f9a kh\u00f4.<\/p>\n

B\u1ea3ng 1 tr\u00ecnh b\u00e0y c\u00e1c qu\u1ea7n th\u1ec3 r\u1eebng kh\u00e1c nhau t\u1ea1i khu v\u1ef1c nghi\u00ean c\u1ee9u c\u1ee7a khu B\u1ea3o t\u1ed3n t\u1ef1 nhi\u00ean B\u00ecnh Ch\u00e2u Ph\u01b0\u1edbc B\u1eedu.<\/p>\n

T\u1ea1i ki\u1ec3u r\u1eebng \u1ea9m th\u01b0\u1eddng xanh I v\u1edbi t\u1ef7 l\u1ec7 t\u1ed5ng di\u1ec7n t\u00edch ngang l\u00e0 84 % (G%) th\u00ec Tr\u00e0m Melaleuca leucadendron <\/em>L. (Myrtaceae) <\/em>chi\u1ebfm\u01b0u th\u1ebf. Ki\u1ec3u r\u1eebng n\u00e0y ph\u00e2n b\u1ed1 t\u1eadp trung t\u1ea1i nh\u1eefng v\u00f9ng tr\u0169ng kh\u00e1 r\u1ed9ng. Nh\u1eefng v\u00f9ng tr\u0169ng n\u00e0y t\u1ecf ra \u0111\u00e3 ch\u1ecbu \u1ea3nh h\u01b0\u1edfng c\u1ee7a n\u01b0\u1edbc \u1ee9 \u0111\u1ecdng v\u00e0o m\u00f9a m\u01b0a. T\u1ea5t c\u1ea3 c\u00e1c lo\u00e0i trong ki\u1ec3u r\u1eebng n\u00e0y kh\u00f4ng r\u1ee5ng l\u00e1 v\u00e0o m\u00f9a kh\u00f4. So v\u1edbi c\u00e1c ki\u1ec3u r\u1eebng \u0111\u01b0\u1ee3c nghi\u00ean c\u1ee9u kh\u00e1c, ki\u1ec3u r\u1eebng n\u00e0y c\u00f3 th\u00e0nh ph\u1ea7n lo\u00e0i th\u1ea5p nh\u1ea5t.<\/p>\n

Ki\u1ec3u r\u1eebng \u1ea9m th\u01b0\u1eddng xanh II th\u01b0\u1eddng ph\u00e2n b\u1ed1 tr\u1ef1c ti\u1ebfp ngay tr\u00ean m\u00e9p ngo\u00e0i c\u1ee7a v\u00f9ng tr\u0169ng. C\u00e1c lo\u00e0i \u01b0u th\u1ebf c\u1ee7a ki\u1ec3u r\u1eebng n\u00e0y l\u00e0 Sao D\u1ea7u (Dipterocarpaceae)<\/em>, D\u1ea7u c\u00e1t Dipterocarpus caudatus spp. caudatus – <\/em>lo\u00e0i \u0111\u00e3 \u0111\u01b0\u1ee3c c\u00f4ng nh\u1eadn trong S\u00e1ch \u0110\u1ecf c\u1ee7a UICN 2000 – v\u00e0 Th\u1ecb r\u1eebng Diospyros decandra <\/em>Lour. (Ebenaceae)<\/em>. Ngo\u00e0i ra, m\u1ed9t s\u1ed1 lo\u00e0i kh\u00e1c c\u0169ng \u0111\u01b0\u1ee3c xem l\u00e0 quan tr\u1ecdng nh\u01b0 S\u1ebfn Shorea roxburghii <\/em>G. Don(Dipterocarpaceae) <\/em>v\u1edbi 8% v\u00e0 C\u1ea9m li\u00ean Pentacme siamensis (Miq.) (Dipterocarpaceae)<\/em> v\u1edbi 4%. Ki\u1ec3u r\u1eebng n\u00e0y \u0111\u00e3 chi\u1ebfm g\u1ea5p \u0111\u00f4i t\u1ed5ng di\u1ec7n t\u00edch ngang so v\u1edbi r\u1eebng n\u1eb1m trong v\u00f9ng tr\u0169ng. Ki\u1ec3u r\u1eebng n\u00e0y lu\u00f4n lu\u00f4n xanh l\u00e1 v\u00e0o m\u00f9a kh\u00f4.<\/p>\n

Ki\u1ec3u r\u1eebng \u1ea9m th\u01b0\u1eddng xanh III n\u1eb1m tr\u00ean \u0111\u1ecba b\u00e0n c\u00f3 \u0111\u1ed9 cao kho\u1ea3ng 31m so v\u1edbi m\u1eb7t bi\u1ec3n v\u01b0\u1ee3t h\u1eb3n hai ki\u1ec3u r\u1eebng n\u1eb1m th\u1ea5p h\u01a1n v\u1eeba n\u00eau b\u00ean tr\u00ean. Th\u00e0nh ph\u1ea7n lo\u00e0i \u01b0u th\u1ebf g\u1ed3m c\u00f3 S\u1ebfn – Shorea roxburghii <\/em>G. Don (Dipteocarpaceae)<\/em> v\u1edbi G = 52% v\u00e0 Th\u1ecb r\u1eebng Diospyros candolleana<\/em> Wight (Ebenaceae)<\/em> v\u1edbi 10%. Ngo\u00e0i ra c\u00f2n c\u00f3 nh\u1eefng lo\u00e0i m\u1ecdc xen l\u1eabn kh\u00e1c t\u01b0\u01a1ng \u0111\u1ed1i quan tr\u1ecdng nh\u01b0 D\u1ea7u c\u00e1t Dipterocarpus caudatus spp. caudatus <\/em>v\u1edbi 4%, Tai ngh\u00e9 Aporusa planchioniana <\/em>Bail. (Euphorbiaceae)<\/em> v\u1edbi 3% v\u00e0 Tr\u00e2m Sygyzium sp. (Myrtaceae<\/em>) v\u1edbi 3%. Ki\u1ec3u r\u1eebng n\u00e0y c\u00f3 t\u1ea7ng t\u00e1n lu\u00f4n lu\u00f4n xanh v\u00e0 m\u1ed9t chi\u1ec1u cao v\u01b0\u1ee3t h\u1eb3n c\u00e1c ki\u1ec3u r\u1eebng kh\u00e1c (xem b\u1ea3ng 1). S\u1ed1 l\u01b0\u1ee3ng lo\u00e0i c\u0169ng t\u01b0\u01a1ng \u0111\u1ed1i cao h\u01a1n.<\/p>\n

Ki\u1ec3u r\u1eebng kh\u1ed9p IV, v\u1edbi \u0111\u1ed9 cao 39m so v\u1edbi m\u1eb7t bi\u1ec3n, l\u00e0 ki\u1ec3u r\u1eebng n\u1eb1m tr\u00ean \u0111\u1ecba b\u00e0n cao nh\u1ea5t so v\u1edbi c\u00e1c ki\u1ec3u r\u1eebng nghi\u00ean c\u1ee9u kh\u00e1c. C\u00e1c lo\u00e0i \u01b0u th\u1ebf c\u1ee7a r\u1eebng n\u00e0y bao g\u1ed3m S\u1ebfn Shorea roxburghii <\/em>G.Don (Dipteocarpaceae<\/em>) ch\u1ec9 c\u00f2n v\u1edbi 19%, Shorea sp. v\u1edbi<\/em> 13% v\u00e0 V\u00ean v\u00ean Anisoptera costata <\/em>Korth. (Dipterocarpaceae) <\/em>v\u1edbi 11%. M\u1ed9t s\u1ed1 lo\u00e0i kh\u00e1c t\u01b0\u01a1ng \u0111\u1ed1i quan tr\u1ecdng c\u00f3 th\u1ec3 k\u1ec3 \u0111\u1ebfn l\u00e0 Tai ngh\u00e9 Aporusa planchioniana <\/em>Bail. (Euphorbiaceae)<\/em> v\u1edbi 10% v\u00e0 D\u00e0nh d\u00e0nh Gardenia philastri (Rubiaceae)<\/em> v\u1edbi 2%. Nh\u1eefng lo\u00e0i \u01b0u th\u1ebf thu\u1ed9c t\u1ea7ng cao nh\u1ea5t c\u1ee7a ki\u1ec3u r\u1eebng n\u00e0y h\u1ea7u h\u1ebft \u0111\u1ec1u r\u1ee5ng r\u00e1 v\u00e0o m\u00f9a kh\u00f4. C\u00e1c th\u00f4ng s\u1ed1 c\u1ee7a ki\u1ec3u r\u1eebng n\u00e0y (v\u00ed d\u1ee5: t\u1ed5ng di\u1ec7n t\u00edch ngang, chi\u1ec1u cao to\u00e0n th\u00e2n, chi\u1ec1u d\u01b0\u1edbi c\u00e0nh, \u0111\u01b0\u1eddng k\u00ednh trung b\u00ecnh) \u0111\u1ec1u th\u1ea5p h\u01a1n ki\u1ec3u r\u1eebng III, m\u1eb7c d\u00f9 s\u1ed1 l\u01b0\u1ee3ng th\u00e0nh ph\u1ea7n lo\u00e0i t\u01b0\u01a1ng \u0111\u01b0\u01a1ng nhau.<\/p>\n

Ki\u1ec3u r\u1eebng kh\u1ed9p V (v\u1ecb tr\u00ed khu ti\u00eau chu\u1ea9n \u0111\u01b0\u1ee3c ch\u1ecdn c\u1ee7a ki\u1ec3u r\u1eebng n\u00e0y n\u1eb1m c\u00e1ch b\u1edd bi\u1ec3n \u0110\u00f4ng 200m) c\u00f3 t\u1ed5ng di\u1ec7n t\u00edch ngang l\u1edbn nh\u1ea5t l\u00e0 30m2<\/sup>\/ha v\u00e0 m\u1eadt \u0111\u1ed9 qu\u1ea7n th\u1ec3 cao nh\u1ea5t l\u00e0 608c\u00e2y\/ha. T\u1ea1i \u0111\u00e2y, c\u00e1c lo\u00e0i trong h\u1ecd Sao d\u1ea7u kh\u00f4ng c\u00f2n chi\u1ebfm \u01b0u th\u1ebf n\u1eefa m\u00e0 \u0111\u01b0\u1ee3c thay th\u1ebf b\u1eb1ng B\u00ecnh linh Vitex pubescens <\/em>Vahl. (Verbenaceae)<\/em> v\u1edbi 32% v\u00e0<\/em> B\u1eb1ng l\u0103ng Lagerstroemia calyculata <\/em>S. Kurz (Lythraceae) <\/em>v\u1edbi 27% t\u1ef7 l\u1ec7 t\u1ed5ng di\u1ec7n t\u00edch ngang. M\u1ed9t s\u1ed1 lo\u00e0i kh\u00e1c kh\u00e1 ph\u1ed5 bi\u1ebfn l\u00e0 Tr\u01b0\u1eddng Xerospermum sp. (Sapindaceae)<\/em> v\u1edbi 7%, Tr\u00e2m Syzygium sp. (Myrtaceae) <\/em>v\u1edbi 5% v\u00e0 Th\u00e0nh ng\u1ea1nh Cratoxylon formosum <\/em>(Korth. Benth. et Hook) (Guttiferae<\/em>) ch\u1ec9 v\u1edbi 3%.V\u00e0o m\u00f9a kh\u00f4 h\u1ea7u nh\u01b0 t\u1ea5t c\u1ea3 c\u00e1c lo\u00e0i t\u1eeb t\u1ea7ng cao \u0111\u1ebfn t\u1ea7ng th\u1ea5p \u0111\u1ec1u r\u1ee5ng l\u00e1.<\/p>\n

Trong \u0111i\u1ec1u ki\u1ec7n c\u00f9ng m\u1ed9t l\u01b0\u1ee3ng m\u01b0a h\u00e0ng n\u0103m t\u1ea1i B\u00ecnh Ch\u00e2u th\u00ec c\u00e1c ki\u1ec3u r\u1eebng “kh\u00f4 r\u1ee5ng l\u00e1” c\u00f3 khuynh h\u01b0\u1edbng gia t\u0103ng v\u1ec1 di\u1ec7n t\u00edch g\u1ed1c c\u0169ng nh\u01b0 m\u1eadt \u0111\u1ed9 c\u00e2y. Trong khi \u0111\u00f3 ki\u1ec3u r\u1eebng \u1ea9m th\u01b0\u1eddng xanh III \u0111\u1ea1t \u0111\u01b0\u1ee3c chi\u1ec1u cao nh\u1ea5t v\u00e0 ki\u1ec3u r\u1eebng III (th\u01b0\u1eddng xanh) v\u00e0 ki\u1ec3u r\u1eebng IV (b\u00e1n thay l\u00e1) chi\u1ebfm \u0111\u01b0\u1ee3c th\u00e0nh ph\u1ea7n lo\u00e0i phong ph\u00fa nh\u1ea5t.<\/p>\n

\u0110\u1ea5t <\/em><\/h3>\n

Nghi\u00ean c\u1ee9u \u0111\u1ea5t gi\u00fap ch\u00fang ta ph\u00e1t hi\u1ec7n \u0111\u01b0\u1ee3c c\u00e1c nguy\u00ean nh\u00e2n d\u1eabn \u0111\u1ebfn s\u1ef1 bi\u1ebfn th\u1ec3 c\u1ee7a c\u1ea5u t\u1ea1o r\u1eebng v\u00e0 c\u00e1c ki\u1ec3u r\u1eebng tr\u00ean m\u1ed9t \u0111\u1ecba b\u00e0n v\u00f4 c\u00f9ng nh\u1ecf b\u00e9. Luyen v\u00e0 Fiedler (1995) \u0111\u00e3 \u0111\u01b0a ra m\u1ed9t s\u1ed1 \u0111\u1ea5t ti\u00eau bi\u1ec3u cho Vi\u1ec7t Nam trong chu\u1ed7i \u0111\u1ea5t c\u00e1t ven bi\u1ec3n. Ch\u00fang \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i theo c\u00e1c \u0111\u1ecba ph\u1eadn kh\u00e1c nhau nh\u01b0 \u0111\u1ea5t c\u00e1t tr\u00ean b\u00e3i bi\u1ec3n, tr\u00ean \u0111\u1ee5n c\u00e1t bay cao v\u00e0 th\u1ea5p, tr\u00ean \u0111\u1ee5n c\u00e1t c\u1ed1 \u0111\u1ecbnh k\u1ec1 s\u00e1t m\u1ef1c n\u01b0\u1edbc ng\u1ea7m v\u00e0 t\u1ea1i c\u00e1c \u0111\u1ecba \u0111i\u1ec3m ng\u1eadp n\u01b0\u1edbc. C\u00e1c d\u1ea1ng \u0111\u1ea5t n\u00e0y c\u0169ng \u0111\u01b0\u1ee3c t\u00ecm th\u1ea5y trong khu v\u1ef1c nghi\u00ean c\u1ee9u t\u1ea1i B\u00ecnh Ch\u00e2u Ph\u01b0\u1edbc B\u1eedu. T\u00e1c gi\u1ea3 Moormann(1961) \u0111\u00e3 \u0111\u01b0a lo\u1ea1i \u0111\u1ea5t c\u00e1t th\u00f4 n\u00e0y v\u00e0o nh\u00f3m eutric regosols v\u00e0 ph\u00e2n c\u1ea5p ch\u00fang th\u00e0nh hai nh\u00f3m “regosols tr\u00ean c\u00e1t bi\u1ec3n m\u1edbi” v\u00e0 “regosols tr\u00ean \u0111\u1ea5t c\u00e1t bi\u1ec3n c\u1ed5”.<\/p>\n

B\u1ea3ng 2 cho th\u1ea5y, th\u00e0nh ph\u1ea7n c\u00e1t trong \u0111\u1ea5t c\u1ee7a 4 ki\u1ec3u r\u1eebng (I, II, III v\u00e0 IV) chi\u1ebfm kho\u1ea3ng 90%, ch\u1ee7 y\u1ebfu l\u00e0 c\u00e1t h\u1ea1t v\u1eeba v\u00e0 c\u00e1t m\u1ecbn. \u0110\u1ea5t c\u1ee7a r\u1eebng kh\u00f4 r\u1ee5ng l\u00e1 ki\u1ec3u V v\u1edbi g\u1ea7n 60 % c\u00e1t h\u1ea1t th\u00f4 to trong t\u1ed5ng kh\u1ed1i l\u01b0\u1ee3ng th\u00e0nh ph\u1ea7n c\u00e1t kho\u1ea3ng 85 %, ch\u1ec9 l\u00e0 m\u1ed9t ngo\u1ea1i l\u1ec7.<\/p>\n

B\u1ea3ng 1 C\u00e1c th\u00f4ng s\u1ed1 ch\u00ednh c\u1ee7a n\u0103m ki\u1ec3u r\u1eebng (I-V) t\u1ea1i B\u00ecnh Ch\u00e2u Ph\u01b0\u1edbc B\u1eedu<\/strong><\/p>\n\n\n\n\n\n
Ki\u1ec3u r\u1eebng<\/strong><\/p>\n

Ph\u00e2n v\u00f9ng\/Kh\u00f4ng ph\u00e2n v\u00f9ng <\/strong><\/td>\n

R\u1eebng tr\u00e0m Melaleuca<\/em> I<\/strong><\/p>\n

Kh\u00f4ng ph\u00e2n v\u00f9ng<\/strong><\/td>\n

R\u1eebng \u1ea9m th\u01b0\u1eddng xanh II<\/strong><\/p>\n

Kh\u00f4ng ph\u00e2n v\u00f9ng<\/strong><\/td>\n

R\u1eebng \u1ea9m th\u01b0\u1eddng xanh III<\/strong><\/p>\n

Kh\u00f4ng ph\u00e2n v\u00f9ng<\/strong><\/td>\n

R\u1eebng kh\u1ed9p IV<\/strong><\/p>\n

Ph\u00e2n v\u00f9ng<\/strong><\/td>\n

R\u1eebng kh\u00f4 r\u1ee5ng l\u00e1 <\/strong><\/p>\n

V<\/strong><\/p>\n

Kh\u00f4ng ph\u00e2n v\u00f9ng<\/strong><\/td>\n<\/tr>\n

Lo\u00e0i \u01b0u th\u1ebf<\/p>\n

(G%)<\/td>\n

Melaleuca leucadendron<\/em><\/p>\n

(84%)<\/em><\/td>\n

Dipterocarpus caudatus (43%)<\/em><\/p>\n

Diospyros decandra<\/em><\/p>\n

(11%)<\/em><\/td>\n

Shorea roxburghii (52%)<\/em><\/p>\n

Diospyros candolleana<\/em><\/p>\n

(10%)<\/em><\/td>\n

Shorea roxburghii<\/em><\/p>\n

(19%)<\/em><\/p>\n

Shorea <\/em>sp.<\/p>\n

(13%)<\/em><\/p>\n

Anisoptera costata (11%)<\/em><\/td>\n

Vitex pubescens <\/em><\/p>\n

(32%)<\/em><\/p>\n

Lagerstroemia<\/em><\/p>\n

calyculata<\/em><\/p>\n

(27%)<\/em><\/td>\n<\/tr>\n

T\u1ed5ng di\u1ec7n t\u00edch g\u1ed1c G (m2<\/sup>\/ha)<\/p>\n

M\u1eadt \u0111\u1ed9 c\u00e2y N\/ha<\/p>\n

10-30cm D1,3 v\u00e0 >30cm D1,3<\/p>\n

\u0110\u01b0\u1eddng k\u00ednh trung b\u00ecnh Dg (cm)<\/p>\n

Chi\u1ec1u cao trung b\u00ecnh d\u01b0\u1edbi c\u00e0nh Hg (m)<\/p>\n

Chi\u1ec1u cao to\u00e0n th\u00e2n Ho (m)<\/p>\n

S\u1ed1 l\u01b0\u1ee3ng lo\u00e0i<\/td>\n

5,3<\/p>\n

328<\/p>\n

4<\/p>\n

13,3<\/p>\n

6,7<\/p>\n

8,3<\/p>\n

5<\/td>\n

11,8<\/p>\n

392<\/p>\n

32<\/p>\n

17.4<\/p>\n

9,4<\/p>\n

11,9<\/p>\n

14<\/td>\n

26,1<\/p>\n

416<\/p>\n

100<\/p>\n

20,3<\/p>\n

14,6<\/p>\n

19,4<\/p>\n

38<\/td>\n

17,3<\/p>\n

440<\/p>\n

72<\/p>\n

18,1<\/p>\n

12,5<\/p>\n

16,6<\/p>\n

39<\/td>\n

30,1<\/p>\n

484<\/p>\n

124<\/p>\n

21,6<\/p>\n

14,0<\/p>\n

16,6<\/p>\n

25<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

* C\u00e1c ki\u1ec3u r\u1eebng II,III v\u00e0 IV b\u1ecb t\u00e1c \u0111\u1ed9ng nhi\u1ec1u do c\u01b0a tr\u1ed9m<\/em><\/p>\n

V\u00e0o m\u00f9a m\u01b0a, m\u1eb7c d\u00f9 nh\u1eadn c\u00f9ng m\u1ed9t l\u01b0\u1ee3ng m\u01b0a nh\u01b0 nhau, t\u00ecnh tr\u1ea1ng n\u01b0\u1edbc c\u1ee7a c\u00e1c ki\u1ec3u r\u1eebng \u1ea9m th\u01b0\u1eddng xanh I, II d\u01b0\u1eddng nh\u01b0 c\u00f3 xu h\u01b0\u1edbng \u0111\u01b0\u1ee3c b\u1ed5 xung c\u1ea3i thi\u1ec7n; trong khi \u1ea5y t\u1ea1i c\u00e1c ki\u1ec3u r\u1eebng th\u01b0\u1eddng xanh III \u0111\u1ebfn r\u1eebng kh\u1ed9p IV v\u00e0 r\u1eebng r\u1ee5ng l\u00e1 V, l\u01b0\u1ee3ng n\u01b0\u1edbc trong \u0111\u1ea5t c\u00f3 v\u1ebb m\u1ed7i l\u00fac m\u1ed9t khan hi\u1ebfm h\u01a1n. Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y c\u00f3 th\u1ec3 l\u00fd gi\u1ea3i r\u1eb1ng, ch\u00ednh c\u1ea5u t\u1ea1o c\u00e1t th\u00f4 trong ki\u1ec3u r\u1eebng V v\u1edbi nhi\u1ec1u khe h\u1edf \u0111\u00e3 l\u00e0m gi\u1ea3m kh\u1ea3 n\u0103ng gi\u1eef n\u01b0\u1edbc l\u1ea1i trong \u0111\u1ea5t.<\/p>\n

Tr\u1eef l\u01b0\u1ee3ng c\u00e1c nguy\u00ean t\u1ed1 ph\u00e2n t\u00edch trong \u0111\u1ea5t, k\u1ec3 t\u1eeb m\u1eb7t xu\u1ed1ng \u0111\u1ebfn \u0111\u1ed9 s\u00e2u 50cm t\u1ea1i m\u1ed7i ki\u1ec3u r\u1eebng nghi\u00ean c\u1ee9u, d\u01b0\u1eddng nh\u01b0 \u0111\u1ea7y \u0111\u1ee7. Trong qu\u00e1 tr\u00ecnh n\u01b0\u1edbc ng\u00e0y c\u00e0ng gi\u1ea3m th\u00ec tr\u1eef l\u01b0\u1ee3ng Kali, Mangan, Nh\u00f4m v\u00e0 AKe c\u0169ng c\u00e0ng gi\u1ea3m theo. \u0110\u1ed1i v\u1edbi Calci v\u00e0 Magnesium, th\u00ec tr\u1eef l\u01b0\u1ee3ng c\u1ee7a ch\u00fang c\u00f3 tr\u1ecb s\u1ed1 cao nh\u1ea5t trong ki\u1ec3u r\u1eebng \u1ea9m th\u01b0\u1eddng xanh III. Nh\u00ecn chung, nh\u1eefng tr\u1eef l\u01b0\u1ee3ng n\u00e0y c\u00e0ng nhi\u1ec1u khi s\u1ef1 kh\u00f4 h\u1ea1n c\u1ee7a r\u1eebng c\u00e0ng cao b\u1edfi v\u00ec s\u1ef1 r\u1eeda tr\u00f4i di\u1ec5n ra r\u1ea5t \u00edt trong \u0111i\u1ec1u ki\u1ec7n kh\u00f4 h\u1ea1n.<\/p>\n

B\u1ea3ng 2 M\u00f4 t\u1ea3 c\u00e1c ki\u1ec3u \u0111\u1ea5t l\u1ea5y \u1edf \u0111\u1ed9 s\u00e2u 50cm trong c\u00e1c ki\u1ec3u r\u1eebng nghi\u00ean c\u1ee9u<\/strong><\/p>\n

t\u1ea1i B\u00ecnh Ch\u00e2u Ph\u01b0\u1edbc B\u1eedu<\/strong><\/p>\n\n\n\n\n\n
Ki\u1ec3u r\u1eebng <\/strong><\/td>\nR\u1eebng Tr\u00e0m Melaleuca<\/em> I<\/strong><\/td>\nR\u1eebng \u1ea9m th\u01b0\u1eddng xanh II<\/strong><\/td>\nR\u1eebng \u1ea9m th\u01b0\u1eddng xanh III<\/strong><\/td>\nR\u1eebng kh\u1ed9p IV<\/strong><\/td>\nR\u1eebng r\u1ee5ng l\u00e1 <\/strong><\/p>\n

V<\/strong><\/td>\n<\/tr>\n

\u0110\u1ed9 cao so v\u1edbi m\u1eb7t bi\u1ec3n (m)<\/p>\n

Th\u00e0nh ph\u1ea7n c\u1ea5u t\u1ea1o \u0111\u1ea5t (%)<\/strong><\/p>\n

h\u1ea1t th\u00f4 (2-0,63mm)<\/p>\n

h\u1ea1t v\u1eeba (0,63-0,2mm)<\/p>\n

h\u1ea1t m\u1ecbn (0,2-0,063mm)<\/p>\n

h\u1ea1t m\u1ecbn (0,063-0,002mm)<\/p>\n

s\u00e9t (< 0,002mm)<\/td>\n

14<\/p>\n

2<\/p>\n

61<\/p>\n

35<\/p>\n

2<\/p>\n

0<\/td>\n

16<\/p>\n

1<\/p>\n

60<\/p>\n

36<\/p>\n

2<\/p>\n

1<\/td>\n

31<\/p>\n

1<\/p>\n

48<\/p>\n

41<\/p>\n

3<\/p>\n

8<\/td>\n

39<\/p>\n

1<\/p>\n

53<\/p>\n

34<\/p>\n

4<\/p>\n

8<\/td>\n

12<\/p>\n

59<\/p>\n

16<\/p>\n

10<\/p>\n

7<\/p>\n

8<\/td>\n<\/tr>\n

Cation (kg\/ha)<\/strong><\/p>\n

Kalium K<\/p>\n

Natri Na<\/p>\n

Calci Ca<\/p>\n

Magne Mg<\/p>\n

S\u1eaft Fe<\/p>\n

Mangan Mn<\/p>\n

Nh\u00f4m Al<\/p>\n

AKe[kmol IE\/ha}*<\/p>\n

pH (H2O)<\/td>\n

29<\/p>\n

113<\/p>\n

522<\/p>\n

69<\/p>\n

0<\/p>\n

2<\/p>\n

270<\/p>\n

36<\/p>\n

5,5<\/td>\n

40<\/p>\n

110<\/p>\n

659<\/p>\n

182<\/p>\n

0<\/p>\n

47<\/p>\n

432<\/p>\n

47<\/p>\n

4,9<\/td>\n

109<\/p>\n

121<\/p>\n

779<\/p>\n

345<\/p>\n

0<\/p>\n

65<\/p>\n

774<\/p>\n

72<\/p>\n

5,1<\/td>\n

105<\/p>\n

116<\/p>\n

232<\/p>\n

115<\/p>\n

61<\/p>\n

12<\/p>\n

1422<\/p>\n

76<\/p>\n

4,2<\/td>\n

02<\/p>\n

144<\/p>\n

353<\/p>\n

212<\/p>\n

0<\/p>\n

77<\/p>\n

1800<\/p>\n

105<\/p>\n

4,9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

* Kh\u1ea3 n\u0103ng trao \u0111\u1ed5i cation <\/em><\/p>\n

\u0110o l\u01b0\u1ee3ng n\u01b0\u1edbc trong c\u00e2y <\/strong><\/p>\n

Vi\u1ec7c \u0111o nWP<\/em> v\u00e0 nOP<\/em> \u0111\u01b0\u1ee3c ti\u1ebfn h\u00e0nh v\u00e0o th\u1eddi gian kh\u00f4 nh\u1ea5t t\u1eeb 19-25 th\u00e1ng ba n\u0103m 1996. V\u00e0o th\u1eddi \u0111i\u1ec3m n\u00e0y, m\u1ed9t v\u00e0i lo\u00e0i nh\u01b0 B\u1eb1ng l\u0103ng \u0111\u00e3 ho\u00e0n to\u00e0n r\u1ee5ng l\u00e1, do \u0111\u00f3 kh\u00f4ng th\u1ec3 \u0111\u01b0a ch\u00fang v\u00e0o ch\u01b0\u01a1ng tr\u00ecnh nghi\u00ean c\u1ee9u sinh th\u00e1i \u0111\u01b0\u1ee3c. Song th\u1eddi \u0111i\u1ec3m n\u00e0y l\u1ea1i r\u1ea5t thu\u1eadn l\u1ee3i cho s\u1ef1 x\u00e1c \u0111\u1ecbnh nh\u1eefng tr\u1ecb s\u1ed1 t\u1ed1i \u0111a c\u1ee7a c\u00e2y, \u0111\u1eb7c bi\u1ec7t l\u00e0 t\u1ea1i ki\u1ec3u r\u1eebng kh\u00f4 thay l\u00e1 V.<\/p>\n

B\u1ea3ng 3 tr\u00ecnh b\u00e0y s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa c\u00e1c tr\u1ecb s\u1ed1 nWP<\/em> v\u00e0 nOP<\/em> \u0111o \u0111\u01b0\u1ee3c v\u00e0o c\u00e1c bu\u1ed5i tr\u01b0a v\u00e0 ban \u0111\u00eam t\u1ea1i 5 ki\u1ec3u r\u1eebng nghi\u00ean c\u1ee9u. V\u00e0o bu\u1ed5i tr\u01b0a, khi nhi\u1ec7t \u0111\u1ed9 ngo\u00e0i tr\u1eddi l\u00ean cao, c\u00e1c tr\u1ecb s\u1ed1 \u0111o \u0111\u01b0\u1ee3c c\u0169ng cao h\u01a1n ban \u0111\u00eam, b\u1edfi v\u00ec h\u01a1i n\u01b0\u1edbc trong kh\u00f4ng kh\u00ed t\u0103ng l\u00ean v\u00e0o ban \u0111\u00eam v\u00e0 c\u00e1c kh\u00ed kh\u1ed5ng c\u0169ng \u0111\u00f3ng k\u00edn. Tr\u1ecb s\u1ed1 \u0111o c\u1ee7a nWP<\/em> v\u00e0o l\u00fac ban \u0111\u00eam bi\u1ec3u l\u1ed9 \u0111\u01b0\u1ee3c s\u1ef1 c\u00e2n b\u1eb1ng gi\u1eefa c\u00e2y v\u00e0 m\u00f4i tr\u01b0\u1eddng \u0111\u1ea5t v\u00e0 tr\u1ecb s\u1ed1 \u1ea5y c\u0169ng l\u00e0 tr\u1ecb s\u1ed1 t\u01b0\u01a1ng \u1ee9ng v\u1edbi l\u01b0\u1ee3ng n\u01b0\u1edbc trong c\u00e2y l\u00fac b\u1ea5y gi\u1edd (KREEB 1990; WILLERT et al. 1995).<\/p>\n

B\u1ea3ng 3 c\u0169ng cho th\u1ea5y r\u1eb1ng ki\u1ec3u r\u1eebng \u1ea9m th\u01b0\u1eddng xanh I, trong t\u00ecnh h\u00ecnh th\u1eddi ti\u1ebft kh\u00e1 kh\u00f4, \u0111\u00e3 \u0111\u1ea1t tr\u1ecb s\u1ed1 nWP<\/em> r\u1ea5t th\u1ea5p v\u00e0o l\u00fac ban \u0111\u00eam. Tr\u1ecb s\u1ed1 n\u00e0y kh\u00f4ng ch\u00eanh l\u1ec7ch m\u1ea5y so v\u1edbi tr\u1ecb s\u1ed1 chu\u1ea9n. T\u1ea5t c\u1ea3 6 m\u1eabu th\u00ed nghi\u1ec7m v\u1edbi Tr\u00e0m Melaleuca leucadendron<\/em> \u0111\u01b0\u1ee3c \u0111o c\u00f9ng l\u00fac \u1ea5y \u0111\u1ec1u bi\u1ec3u hi\u1ec7n nh\u1eefng \u0111i\u1ec1u ki\u1ec7n n\u01b0\u1edbc trong \u0111\u1ea5t r\u1ea5t thu\u1eadn l\u1ee3i, m\u1eb7c d\u00f9 \u0111ang v\u00e0o m\u00f9a kh\u00f4. Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y c\u0169ng di\u1ec5n ra t\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady t\u1ea1i nh\u1eefng ki\u1ec3u r\u1eebng \u1ea9m th\u01b0\u1eddng xanh II v\u00e0 III. Trong khi \u0111\u00f3 th\u00ec tr\u1ecb s\u1ed1 nWP<\/em> c\u1ee7a ki\u1ec3u r\u1eebng kh\u1ed9p IV l\u1ea1i cao h\u01a1n g\u1ea5p b\u1ed9i v\u00e0o ban \u0111\u00eam. Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y n\u00f3i l\u00ean t\u00ecnh tr\u1ea1ng kh\u00e1 c\u0103ng th\u1eb3ng c\u1ee7a n\u01b0\u1edbc trong \u0111\u1ea5t. Th\u00eam v\u00e0o \u0111\u00f3, s\u1ef1 ch\u00eanh l\u1ec7ch l\u1edbn so v\u1edbi tr\u1ecb s\u1ed1 chu\u1ea9n c\u0169ng ch\u1ee9ng minh \u0111\u01b0\u1ee3c r\u1eb1ng, t\u1ea1i \u0111\u1ecba b\u00e0n nh\u1ecf, t\u00ecnh tr\u1ea1ng c\u1ee7a n\u01b0\u1edbc trong \u0111\u1ea5t bi\u1ebfn \u0111\u1ed5i m\u1ea1nh h\u01a1n. S\u1ef1 kh\u00e1c bi\u1ec7t r\u1ea5t l\u1edbn gi\u1eefa nh\u1eefng tr\u1ecb s\u1ed1 b\u00ecnh qu\u00e2n c\u1ee7a c\u00e1c lo\u00e0i (so s\u00e1nh gi\u1eefa Aporusa<\/em> v\u00e0 Gardenia<\/em>) trong c\u00f9ng m\u1ed9t ki\u1ec3u r\u1eebng kh\u1ed9p IV, sau khi \u0111\u00e3 t\u00ednh c\u00e1c sai s\u1ed1, cho th\u1ea5y r\u1eb1ng nh\u1eefng lo\u00e0i \u1ea5y tuy thu\u1ed9c c\u00f9ng m\u1ed9t kho\u1ea3nh r\u1eebng, song l\u1ea1i m\u1ecdc tr\u00ean c\u00e1c “\u1ed5” \u0111\u1ea5t (\u00f4 \u0111\u1ea5t r\u1ea5t nh\u1ecf) c\u00f3 l\u01b0\u1ee3ng cung c\u1ea5p n\u01b0\u1edbc kh\u00e1c nhau. T\u1ea1i ki\u1ec3u r\u1eebng r\u1ee5ng l\u00e1 V, c\u00e1c tr\u1ecb s\u1ed1 \u0111o \u0111\u01b0\u1ee3c cao m\u1ed9t c\u00e1ch \u0111\u1eb7c bi\u1ec7t. T\u1ea1i \u0111\u00e2y tr\u1ecb s\u1ed1 c\u1ee7a lo\u00e0i Tr\u00e2m Syzygium sp. <\/em>cao h\u01a1n c\u1ea3 nh\u1eefng tr\u1ecb s\u1ed1 hi\u1ebfm th\u1ea5y t\u1ea1i khu v\u1ef1c Chaco c\u1ee7a Paraguay ho\u1eb7c c\u1ee7a v\u00f9ng kh\u00f4 h\u1ea1n Kalahari thu\u1ed9c Ch\u00e2u Phi (xem Mitloehner 1995, 1997a), n\u01a1i m\u00e0 l\u01b0\u1ee3ng m\u01b0a trung b\u00ecnh h\u00e0ng n\u0103m th\u1ea5p h\u01a1n m\u1ed9t c\u00e1ch r\u00f5 r\u1ec7t. Nh\u01b0 v\u1eady, c\u00e1c tr\u1ecb s\u1ed1 nWP<\/em> \u0111o trong \u0111\u00eam ph\u1ea3n \u00e1nh \u0111\u01b0\u1ee3c l\u01b0\u1ee3ng n\u01b0\u1edbc cung \u1ee9ng hi\u1ec7n th\u1eddi c\u1ee7a th\u1ef1c v\u1eadt tr\u00ean t\u1eebng l\u1eadp \u0111\u1ecba t\u01b0\u01a1ng \u1ee9ng. \u0110i\u1ec1u n\u00e0y \u0111\u01b0a \u0111\u1ebfn nh\u1eefng gi\u1ea3i th\u00edch v\u1ec1 s\u1ef1 kh\u00e1c bi\u1ec7t c\u1ee7a c\u00e1c ki\u1ec3u r\u1eebng \u0111\u01b0\u1ee3c nghi\u00ean c\u1ee9u nh\u01b0 sau:<\/p>\n

\u00b7 Ki\u1ec3u r\u1eebng th\u01b0\u1eddng xanh I nh\u1eadn \u0111\u01b0\u1ee3c l\u01b0\u1ee3ng n\u01b0\u1edbc b\u1ed5 xung t\u1eeb ngu\u1ed3n n\u01b0\u1edbc m\u1eb7t v\u00e0o m\u00f9a m\u01b0a v\u00e0 ch\u1ecbu s\u1ef1 \u1ea3nh h\u01b0\u1edfng c\u1ee7a n\u01b0\u1edbc ng\u1eadp t\u1ea1m th\u1eddi,<\/p>\n

\u00b7 Ki\u1ec3u r\u1eebng th\u01b0\u1eddng xanh II nh\u1eadn \u0111\u01b0\u1ee3c n\u01b0\u1edbc b\u1ed5 xung t\u1eeb t\u1ea7ng n\u01b0\u1edbc ng\u1ea7m (so s\u00e1nh lo\u00e0i Dipterocarpus caudatus spp. caudatus <\/em>t\u1ea1i ki\u1ec3u r\u1eebng III, d\u00f9 \u0111o v\u00e0o bu\u1ed5i tr\u01b0a ho\u1eb7c ban \u0111\u00eam, l\u00fac n\u00e0o c\u0169ng c\u00f3 tr\u1ecb s\u1ed1 = 1 bar), <\/em>tuy nhi\u00ean v\u00e0o nh\u1eefng m\u00f9a kh\u00f4 kh\u1eafc nghi\u1ec7t, s\u1ef1 ti\u1ebfp x\u00fac v\u1edbi n\u01b0\u1edbc ng\u1ea7m c\u00f3 th\u1ec3 b\u1ecb gi\u00e1n \u0111o\u1ea1n \u0111\u00f4i l\u00fac,<\/p>\n

\u00b7 Ki\u1ec3u r\u1eebng th\u01b0\u1eddng xanh III nh\u1edd ti\u1ebfp x\u00fac th\u01b0\u1eddng xuy\u00ean v\u1edbi n\u01b0\u1edbc th\u1ea9m th\u1ea5u n\u00ean c\u00f3 \u0111\u01b0\u1ee3c l\u01b0\u1ee3ng n\u01b0\u1edbc cung \u1ee9ng r\u1ea5t t\u1ed1t; m\u1ed9t v\u00e0i lo\u00e0i c\u00f3 th\u1ec3 ti\u1ebfp x\u00fac ph\u1ea7n n\u00e0o v\u1edbi t\u1ea7ng n\u01b0\u1edbc ng\u1ea7m,<\/p>\n

\u00b7 Ki\u1ec3u r\u1eebng m\u01b0a IV ph\u1ea3i \u0111\u1ed1i \u0111\u1ea7u v\u1edbi \u0111i\u1ec1u ki\u1ec7n kh\u00f3 kh\u0103n h\u01a1n v\u1ec1 s\u1ef1 cung \u1ee9ng n\u01b0\u1edbc trong m\u00f9a kh\u00f4; nh\u1eefng lo\u00e0i \u1edf t\u1ea7ng cao v\u1edbi nhu c\u1ea7u l\u1edbn v\u1ec1 n\u01b0\u1edbc ph\u1ea3i r\u1ee5ng l\u00e1,<\/p>\n

\u00b7 Ki\u1ec3u r\u1eebng r\u1ee5ng l\u00e1 V ph\u1ea3i ch\u1ecbu s\u1ef1 thi\u1ebfu n\u01b0\u1edbc gay g\u1eaft trong m\u00f9a kh\u00f4, \u0111i\u1ec1u n\u00e0y \u0111\u00e3 khi\u1ebfn cho \u0111a s\u1ed1 lo\u00e0i ph\u00e1t tri\u1ec3n kh\u1ea3 n\u0103ng t\u00edch lu\u1ef9 n\u01b0\u1edbc trong m\u1ed9t ch\u1eebng m\u1ef1c n\u00e0o \u0111\u00f3.<\/p>\n

Ng\u01b0\u1ee3c l\u1ea1i, k\u1ebft qu\u1ea3 c\u1ee7a nOP<\/em> cho th\u1ea5y r\u1eb1ng c\u00e1c tr\u1ecb s\u1ed1 c\u1ee7a 4 ki\u1ec3u r\u1eebng “\u1ea9m” (I, II, III v\u00e0 IV) kh\u00e1 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng nhau. S\u1ef1 ch\u00eanh l\u1ec7ch c\u1ee7a ch\u00fang so v\u1edbi tr\u1ecb s\u1ed1 chu\u1ea9n c\u0169ng r\u1ea5t th\u1ea5p (xem b\u1ea3ng 3). Ph\u1ea7n kh\u00e1c, c\u00e1c lo\u00e0i c\u00e2y c\u0169ng bi\u1ec3u l\u1ed9 s\u1ef1 t\u01b0\u01a1ng thu\u1ed9c c\u1ee7a m\u00ecnh v\u1edbi c\u00e1c “\u1ed5” \u0111\u1ea5t c\u00f3 \u0111\u1ed9 mu\u1ed1i t\u1eadp trung, nh\u01b0 tr\u01b0\u1eddng h\u1ee3p c\u1ee7a S\u1ebfn Shorea roxburghii <\/em>v\u00e0 Th\u1ecb r\u1eebng Diospyros candolleana <\/em>trong ki\u1ec3u r\u1eebng th\u01b0\u1eddng xanh III. Ki\u1ec3u r\u1eebng r\u1ee5ng l\u00e1 V l\u00e0 n\u01a1i c\u00f3 tr\u1ecb s\u1ed1 nOP<\/em> cao h\u01a1n g\u1ea5p m\u1ea5y l\u1ea7nv\u00e0 c\u0169ng l\u00e0 n\u01a1i m\u00e0 h\u00e0m l\u01b0\u1ee3ng mu\u1ed1i trong \u0111\u1ea5t c\u00f3 n\u1ed3ng \u0111\u1ed9 t\u1eadp trung kh\u00e1 cao. K\u1ebft qu\u1ea3 n\u00e0y c\u0169ng tr\u00f9ng h\u1ee3p v\u1edbi k\u1ebft qu\u1ea3 ph\u00e2n t\u00edch \u0111\u1ea5t: ki\u1ec3u r\u1eebng V c\u00f3 tr\u1ecb s\u1ed1 AKe cao nh\u1ea5t v\u00e0 tr\u1eef l\u01b0\u1ee3ng Cation c\u0169ng cao nh\u1ea5t (xem b\u1ea3ng 2).<\/p>\n

C\u00e1c tr\u1ecb s\u1ed1 nh\u1ea5t th\u1eddi nOP<\/em> v\u00e0 nWP<\/em> c\u00f3 th\u1ec3 \u0111o \u0111\u01b0\u1ee3c b\u1ea5t c\u1ee9 l\u00fac n\u00e0o. Nh\u01b0ng \u0111\u1ec3 c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c nh\u1eefng tr\u1ecb s\u1ed1 k\u0129 l\u01b0\u1ee1ng v\u00e0 l\u00e2u d\u00e0i cho m\u1ed7i lo\u00e0i th\u00ec ph\u1ea3i chu\u1ea9n ho\u00e1 c\u00e1c tr\u1ecb s\u1ed1 nOP<\/em> v\u00e0 nWP<\/em> (Mitloehner 1997a). M\u1ed9t tr\u1ecb s\u1ed1”nOPsat<\/em>” \u0111\u01b0\u1ee3c chu\u1ea9n h\u00f3a s\u1ebd t\u01b0\u01a1ng \u1ee9ng v\u1edbi m\u1ed9t m\u1eabu c\u00e2y th\u00ed nghi\u1ec7m no mu\u1ed1i. N\u00f3 ph\u1ea3n \u00e1nh r\u1ea5t t\u1ed1t \u0111\u1ed9 m\u1eb7n trong \u0111\u1ea5t c\u1ee7a l\u1eadp \u0111\u1ecba.<\/p>\n

\u0110\u1ed3 th\u1ecb \u0111\u1ed1i chi\u1ebfu c\u00e1c tr\u1ecb s\u1ed1 nOP<\/em> v\u00e0 nWP<\/em> \u0111\u01b0\u1ee3c \u0111o v\u00e0o l\u00fac tr\u01b0a c\u0169ng nh\u01b0 l\u00fac \u0111\u00eam c\u1ee7a m\u1ed7i lo\u00e0i c\u00e2y gi\u00fap ch\u00fang ta hi\u1ec3u \u0111\u01b0\u1ee3c: a\/ tr\u1ecb s\u1ed1 tuy\u1ec7t \u0111\u1ed1i nh\u1ea5t th\u1eddi t\u01b0\u01a1ng \u1ee9ng cho m\u1ed7i ki\u1ec3u r\u1eebng v\u00e0 b\/ v\u1ecb tr\u00ed c\u1ee7a m\u1ed9t lo\u00e0i tr\u00ean \u0111\u1ed3 th\u1ecb (khi \u0111o l\u00fac tr\u01b0a v\u00e0 \u0111\u00eam = 1). T\u00f9y theo l\u1eadp \u0111\u1ecba, lo\u00e0i c\u00e2y n\u00e0o \u0111\u1ea1t \u0111\u01b0\u1ee3c tr\u1ecb s\u1ed1 gi\u1edbi h\u1ea1n = 1, th\u00ec t\u1ea1i tr\u1ecb s\u1ed1 nWP<\/em> s\u1ebd di\u1ec5n ra s\u1ef1 r\u1ee5ng l\u00e1 ho\u1eb7c t\u1ea1i tr\u1ecb s\u1ed1 nOP<\/em>, s\u1ef1 ch\u1ebft c\u00e2y. \u0110\u1ed3 th\u1ecb c\u0169ng gi\u00fap ch\u00fang ta nh\u1eadn th\u1ee9c \u0111\u01b0\u1ee3c tr\u1ecb s\u1ed1 c\u1ef1c \u0111\u1ea1i c\u1ee7a c\u1ea3 nOP<\/em> l\u1eabn nWP<\/em> v\u00e0 qua \u0111\u00f3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c ng\u01b0\u1ee1ng stress c\u1ef1c \u0111\u1ea1i m\u00e0 m\u1ed7i lo\u00e0i c\u00f3 th\u1ec3 \u0111\u1ea1t \u0111\u1ebfn theo t\u1eebng l\u1eadp \u0111\u1ecba. Ngo\u00e0i ra \u0111\u1ed3 th\u1ecb c\u00f2n gi\u00fap x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c lo\u00e0i c\u00e2y n\u00e0o th\u00edch h\u1ee3p v\u1edbi ki\u1ec3u r\u1eebng n\u00e0o, tr\u00ean lo\u1ea1i \u0111\u1ea5t n\u00e0o, t\u1eeb \u0111\u00f3 c\u00f3 th\u1ec3 \u0111em ra \u1ee9ng d\u1ee5ng trong vi\u1ec7c tr\u1ed3ng r\u1eebng h\u1ee3p theo nh\u1eefng \u0111i\u1ec1u ki\u1ec7n l\u1eadp \u0111\u1ecba.<\/p>\n

B\u1ea3ng 3 T\u00ecnh h\u00ecnh l\u01b0\u1ee3ng n\u01b0\u1edbc trong c\u00e2y \u0111o \u0111\u01b0\u1ee3c t\u1ea1i B\u00ecnh Ch\u00e2u Ph\u01b0\u1edbc B\u1eedu, x\u1ebfp theo th\u1ee9 t\u1ef1 c\u1ee7a th\u00e0nh ph\u1ea7n \u01b0u th\u1ebf, tr\u1ecb s\u1ed1 b\u00ecnh qu\u00e2n v\u00e0 ch\u00eanh l\u1ec7ch so v\u1edbi tr\u1ecb s\u1ed1 chu\u1ea9n c\u1ee7a 6 c\u00e1 th\u1ec3 l\u1ea5y m\u1eabu t\u1eeb m\u1ed7i lo\u00e0i<\/strong><\/p>\n\n\n\n\n
nWP<\/em><\/strong><\/p>\n

tr\u01b0a<\/strong><\/td>\n

nWP<\/em><\/strong><\/p>\n

\u0111\u00eam<\/strong><\/td>\n

nOP<\/em><\/strong><\/p>\n

tr\u01b0a<\/strong><\/td>\n

nOP<\/em><\/strong><\/p>\n

\u0111\u00eam<\/strong><\/td>\n

nOP<\/em><\/strong><\/p>\n

b\u00e3o ho\u00e0<\/strong><\/td>\n<\/tr>\n

R\u1eebng tr\u00e0m ki\u1ec3u I<\/strong><\/p>\n

Melaleuca leucadendron<\/em><\/p>\n

R\u1eebng \u1ea9m th\u01b0\u1eddng xanh ki\u1ec3u II<\/strong><\/p>\n

Dipterocarpus caudatus<\/em><\/p>\n

Pentacme siamensis<\/em><\/p>\n

R\u1eebng \u1ea9m th\u01b0\u1eddng xanh ki\u1ec3u III<\/strong><\/p>\n

Shorea roxburghii<\/em><\/p>\n

Diospyros candolleana<\/em><\/p>\n

Dipterocarpus caudatus<\/em><\/p>\n

Hopea odorata<\/em><\/p>\n

R\u1eebng kh\u1ed9pki\u1ec3u IV<\/strong><\/p>\n

Aporusa planchoniana<\/em><\/p>\n

Diospyros decandra<\/em><\/p>\n

Gardenia philastri<\/em><\/p>\n

R\u1eebng r\u1ee5ng l\u00e1 ki\u1ec3u V<\/strong><\/p>\n

Vitex pubescens<\/em><\/p>\n

Syzygium sp.<\/em><\/p>\n

Sindora cochinchinensis<\/em><\/td>\n

20 +-5<\/strong><\/p>\n

11<\/strong>+-5<\/p>\n

12<\/strong>+-2<\/p>\n

9+-<\/strong>5<\/p>\n

19+-<\/strong>7<\/p>\n

1+-<\/strong>0<\/p>\n

14<\/strong>+-6<\/p>\n

21<\/strong>+-5<\/p>\n

21<\/strong>+-5<\/p>\n

32<\/strong>+-11<\/p>\n

23<\/strong>+-5<\/p>\n

75<\/strong>+-5<\/p>\n

52<\/strong>+-6<\/td>\n

1<\/strong>+-1<\/p>\n

1<\/strong>+-0<\/p>\n

4<\/strong>+-4<\/p>\n

1+-<\/strong>0<\/p>\n

3+-<\/strong>1<\/p>\n

1+-<\/strong>0<\/p>\n

1+-<\/strong>0<\/p>\n

9<\/strong>+-5<\/p>\n

6<\/strong>+-3<\/p>\n

25<\/strong>+-10<\/p>\n

11<\/strong>+-11<\/p>\n

61<\/strong>+-6<\/p>\n

47<\/strong>+-7<\/td>\n

6<\/strong>+-1<\/p>\n

8+-<\/strong>3<\/p>\n

7+-<\/strong>2<\/p>\n

11+-<\/strong>3<\/p>\n

6+-<\/strong>1<\/p>\n

5+-<\/strong>3<\/p>\n

5+-<\/strong>3<\/p>\n

11<\/strong>+-1<\/p>\n

8<\/strong>+-3<\/p>\n

8<\/strong>+-1<\/p>\n

7<\/strong>+-1<\/p>\n

21<\/strong>+-7<\/p>\n

18<\/strong>+-6<\/td>\n

5+-<\/strong>1<\/p>\n

7+-<\/strong>2<\/p>\n

5+-<\/strong>1<\/p>\n

12+-<\/strong>1<\/p>\n

6+-<\/strong>3<\/p>\n

4+-<\/strong>2<\/p>\n

6+-<\/strong>3<\/p>\n

7<\/strong>+-7<\/p>\n

7<\/strong>+-2<\/p>\n

7<\/strong>+-2<\/p>\n

8<\/strong>+-3<\/p>\n

20<\/strong>+-7<\/p>\n

20<\/strong>+-5<\/td>\n

4+-<\/strong>1<\/p>\n

6+-<\/strong>2<\/p>\n

5+-<\/strong>1<\/p>\n

9+-<\/strong>1<\/p>\n

3+-<\/strong>1<\/p>\n

3+-<\/strong>1<\/p>\n

3+-<\/strong>1<\/p>\n

7<\/strong>+-3<\/p>\n

4<\/strong>+-1<\/p>\n

5<\/strong>+-1<\/p>\n

7<\/strong>+-1<\/p>\n

16<\/strong>+-5<\/p>\n

17<\/strong>+-4<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

nWP: H\u00e0m l\u01b0\u1ee3ng n\u01b0\u1edbc trong c\u00e2y (\u0111\u01a1n v\u1ecb bar), \u0111o l\u00fac tr\u01b0a v\u00e0 \u0111\u00eam<\/em><\/p>\n

nOP: Kh\u1ea3 n\u0103ng th\u1ea9m th\u1ea5u (\u0111\u01a1n v\u1ecb bar), \u0111o l\u00fac tr\u01b0a v\u00e0 \u0111\u00eam<\/em><\/p>\n

nOP: b\u00e3o h\u00f2a (sat): d\u00f9ng so s\u00e1nh (\u0111\u01a1n v\u1ecb bar), \u0111o l\u00fac no n\u01b0\u1edbc <\/em><\/p>\n

K\u1ebft lu\u1eadn <\/strong><\/p>\n

Ph\u01b0\u01a1ng ph\u00e1p \u0111o tr\u1ef1c ti\u1ebfp l\u01b0\u1ee3ng n\u01b0\u1edbc trong c\u00e2y v\u00e0 kh\u1ea3 n\u0103ng th\u00edch nghi v\u1ec1 m\u1eb7t th\u1ea9m th\u1ea5u n\u01a1i c\u00e2y l\u00e0 ph\u01b0\u01a1ng ph\u00e1p c\u00f3 th\u1ec3 gi\u00fap thu th\u1eadp \u0111\u01b0\u1ee3c nh\u1eefng ki\u1ebfn th\u1ee9c sinh th\u00e1i c\u01a1 b\u1ea3n v\u00e0 quan tr\u1ecdng c\u1ee7a l\u1eadp \u0111\u1ecba trong m\u1ed9t th\u1eddi gian ng\u1eafn nh\u1ea5t. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y \u0111\u00e3 \u0111\u01b0\u1ee3c ch\u00fang t\u00f4i \u00e1p d\u1ee5ng t\u1ea1i khu B\u1ea3o t\u1ed3n t\u1ef1 nhi\u00ean B\u00ecnh Ch\u00e2u Ph\u01b0\u1edbc B\u1eedu. C\u00e1c s\u1ed1 li\u1ec7u thu th\u1eadp t\u1ea1i \u0111\u00e2y \u0111\u00e3 gi\u00fap ch\u00fang t\u00f4i ph\u00e2n lo\u1ea1i \u0111\u01b0\u1ee3c c\u00e1c ki\u1ec3u r\u1eebng m\u01b0a nhi\u1ec7t \u0111\u1edbi gi\u00f3 m\u00f9a v\u00e0 c\u00f3 th\u1ec3 s\u1eafp x\u1ebfp ch\u00fang theo t\u1eebng \u01b0u th\u1ebf c\u1ee7a l\u1eadp \u0111\u1ecba. C\u00e1c ki\u1ec3u r\u1eebng m\u01b0a n\u00e0y thay \u0111\u1ed5i trong m\u1ed9t kho\u1ea3ng kh\u00f4ng gian v\u00f4 c\u00f9ng b\u00e9 nh\u1ecf. Nhu c\u1ea7u c\u1ea7n thi\u1ebft v\u1ec1 \u0111\u1ed9 \u1ea9m c\u1ee7a m\u1ed7i lo\u00e0i c\u0169ng nh\u01b0 t\u00ecnh tr\u1ea1ng s\u1eb5n s\u00e0ng cung \u1ee9ng n\u01b0\u1edbc c\u1ee7a l\u1eadp \u0111\u1ecba c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c v\u1edbi \u0111\u1ed9 ch\u00ednh x\u00e1c r\u1ea5t cao. Ch\u00fang t\u00f4i mong \u0111\u01b0\u1ee3c ti\u1ebfp t\u1ee5c c\u00f3 nh\u1eefng c\u00f4ng tr\u00ecnh nghi\u00ean c\u1ee9u t\u01b0\u01a1ng t\u1ef1 t\u1ea1i m\u1ed9t s\u1ed1 \u0111\u1ecba \u0111i\u1ec3m kh\u00e1c thu\u1ed9c \u0110\u00f4ng Nam \u00c1 n\u00f3i chung v\u00e0 Vi\u1ec7t Nam n\u00f3i ri\u00eang \u0111\u1ec3 ki\u1ec3m tra l\u1ea1i l\u1ee3i th\u1ebf c\u1ee7a ph\u01b0\u01a1ng ph\u00e1p n\u00e0y.<\/p>\n

T\u00e0i li\u1ec7u tham kh\u1ea3o ch\u00ednh<\/h4>\n

Bunyavejchewin,S. 1983. Canopy Structure of the Dry Dipterocarp Forest of Thailand . Thai For. Bull. 14,1-132<\/em>.<\/p>\n

Hegner,R. 1979 Nichtimmergruene Waldformationen der Tropen Koelner Geographic Arbeiten 37, 1-410.<\/em><\/p>\n

Khamyong,R.; Pramsarit,S.; Pithong ,J. 1996. The Relationship between Plant Association and Soil Charactersitics in a dry Dipterocarp Forest in Thailand . In: Appanah,S.;Khoo,K.C.(eds.) . Proceeding Fifth Round Table Conference on Dipterocarps . 7.-10-11-1994.<\/em><\/p>\n

Kreeb. K.H.1990. Methoden zur Pflanzenoekologie und Bioindikation<\/em>. Stuttgart,New York.<\/p>\n

Lamprecht,H. 1986 Walbau in den Tropen<\/em> . Hamburg Berlin.<\/p>\n

Lassoie,J.P.; Hinckley ,T.M. (eds.) 1991.Techniques and Approaches in Forest Tree Ecophysiology . Boston.<\/em><\/p>\n

L\u1ed1n, V.B. 1996. Dry Open Dipterocarpus Forests in Vietnam.Vietnamese studies 52(122),67-86.<\/em><\/p>\n

Luyen,N.;Fiedler,H.J. 1995 , Boden – und standortskundliche Gesichtspunkte fuer die Wiederaufforstung von Kahlflaeschen in Vietnam.Forstw. Cbl<\/em>. 114,14-15.<\/p>\n

Mitloehner ,R. 1990.Die Konkurenz der Holzgewaechse in regengruenen Trockenwald des Chaco Boreal , Praguay .<\/em> Goettingen Beitr. Zur Land u.Forstwirschaft in den Tropen u.Subtropen 54,1-177.<\/p>\n

Mitloehner,R. 1995 .Standortcgarakterisierung durch pflanzliche Saugspannung und potentiellen Osmotichen Druck im Chaco Central , Paraguay<\/em>. Gutachten erstellt im Auftrag der Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover , und der Deutschen Gesellschaft fuer Technische Zusammenarbeit (GTZ) , Eschborn.63 Seiten.<\/p>\n

Mitloehner,R. 1996 . Pflanzeinterner Wasserhaushalt und Bestandesstrukture in regengrunen Colophospermum mopane<\/em> – Trockenwaeldern Namibias .Forstarchiv 67, 71-75.<\/p>\n

Mitloehner,R. 1997a . Using Trees a Indicators of Environement Conditions by Measuring their Internal Water Status .Plant research snd Development 45, 33-50.<\/em><\/p>\n

Mitloehner,R.1997b . Plant Water Relations as Incator of Forest Types and Sites Conditions Tested in the Paraguayan Chaco.In:Proc. Internat.IUFRO Symp. On Assessement and Monitoring of Forest in Tropical Dry Regions with Special Refence to Gallery Forests . Brasilia 4.-7.11.1996, in press.<\/em><\/p>\n

Summary<\/h2>\n

The monsoon forests of the mainland South East are characterized by the dominance of Dipterocarpaceae<\/em>. Frequently a very close coexistence of different forest types can be observed. This kind of forest mosaic was investigated in South East Vietnam. After analysis of stand structure and soil characteristics, the dominant species of the respective forest types were investigated physiologically by measuring their midday and pre-dawn plant water potentials and plant osmotic potential under field conditions. The actual water availability of the trees in the late dry season the variety of forest types in the dependence to their respective sites.<\/p>\n","protected":false},"excerpt":{"rendered":"

Th\u1ec1m l\u1ee5c \u0111\u1ecba vùng \u0110ông Nam Á là khu v\u1ef1c ph\u1ea7n l\u1edbn ch\u1ecbu \u1ea3nh h\u01b0\u1edfng c\u1ee7a khí h\u1eadu gió mùa: mùa m\u01b0a (kéo dài t\u1eeb tháng n\u0103m \u0111\u1ebfn tháng m\u01b0\u1eddi) và mùa khô (t\u1eeb tháng m\u01b0\u1eddi m\u1ed9t \u0111\u1ebfn tháng t\u01b0 n\u0103m sau). L\u01b0\u1ee3ng m\u01b0a t\u01b0\u01a1ng \u0111\u1ed1i th\u1ea5p, hàng n\u0103m kho\u1ea3ng 1000 – 1500mm\/n và 5 \u0111\u1ebfn 7 tháng khô (Stott 1991) là nh\u1eefng nhân t\u1ed1 \u0111em l\u1ea1i s\u1ef1 hình thành các ki\u1ec3u r\u1eebng m\u01b0a nhi\u1ec7t \u0111\u1edbi gió mùa.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[],"_links":{"self":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/181"}],"collection":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/comments?post=181"}],"version-history":[{"count":7,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/181\/revisions"}],"predecessor-version":[{"id":19226,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/181\/revisions\/19226"}],"wp:attachment":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/media?parent=181"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/categories?post=181"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/tags?post=181"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}