<\/FONT><\/B> In the global market, Philippine dipterocarps are well known by their international trade name, Philippine mahogany. This group of tree species has played an important role as the primary export commodity and dollar earner of the Philippines for a long time. Of these, Parashorea malaanonan <\/I>belongs to the timber group of Light Red Philippine Mahogany. The volume of log export for this species, however, had dramatically plunged during the last decade (Forestry Statistics, FMB, 1997) because of decline in supply.<\/FONT> <\/FONT> P. malaanonan <\/I>is not only economically-important it is also ecologically significant in that it provides shelter and support to other organisms. It commonly grows together with palms, vines, shrubs and other tree species. It is distributed from the north to the south of the Philippines (Newman et al.<\/I> 1996). The study of Tsumura et al<\/I>. (1996) on the phylogeny of dipterocarps indicated that Parashorea<\/I> is a very close relative of the more common Shorea<\/I>. <\/FONT><\/FONT> <\/FONT> P. malaanonan<\/I> is now threatened by unabated exploitation endangering not only this species but also the other associated species. Although there have been efforts to reverse the adverse effect of massive destruction of forest ecosystems as a result of excessive forest harvesting, very little attention and studies have been directed on the basic science of conservation of forest species as a whole, and much more so on remaining populations of species like Parashorea.<\/I> <\/SPAN><\/FONT><\/FONT> <\/FONT> In Mt. Makiling, Laguna, Philippines, a natural population of P. malaanonan<\/I> spread from the Makiling Botanic Gardens (200 m asl) to the area beyond the Mudspring with an elevation of about 400-450 m asl. The forest has been declared a forest reserve and the population of P. malaanonan<\/I> <\/SPAN>here is probably the only remaining intact population of such species in the country.<\/SPAN><\/FONT><\/FONT> <\/FONT> Basic information about the genetic diversity, mating system and regeneration of P. malaanonan <\/I>were determined lately by the authors for use in crafting strategies for conservation and sustainable management of the species. Very recently an analysis of inbreeding coefficient of progenies, maternal and adults of the population in Mt. Makiling and its implications to the conservation of P. malaanonan<\/I> was undertaken. The monitoring of the growth and survival of regenerants in Mt. Makiling is a continuous activity that provides necessary information for updating the conservation strategy for the population of P. malaanonan<\/I> in the forest reserve<\/SPAN>.<\/FONT> <\/FONT><\/SPAN> <\/FONT> <\/FONT> In this study, the results of the population genetic analysis conducted in 2004 on 61 trees of P. malaanonan <\/I>randomly selected in elevations of 250 – 450 m asl in Mt. Makiling. (Lapitan et al.<\/I> 2005) were evaluated with the results of a related study on the mating system of P. malaanonan<\/I> (Lapitan and Hyun 2005), and the regeneration of the species in the study site to identify conservation strategies for the population in this forest. Wright’s FIS<\/SUB><\/I> was calculated from these data to determine the genetic differences between the samples which can be grouped into two adult populations owing to the different elevation of the area from where they were located. The inbreeding coefficient of the progenies, Fe<\/SUB><\/I>, of the mating system study was also computed and compared with the parental F <\/I>value. The formulae used are:<\/FONT> <\/FONT> Fe<\/SUB><\/I> = (1- tm<\/SUB><\/I>)\/ (1+ tm<\/SUB><\/I>),<\/FONT><\/FONT> <\/SPAN>tm<\/SUB><\/I> = multilocus outcrossing estimate, <\/FONT><\/FONT> <\/SPAN>and<\/FONT><\/FONT> <\/SPAN><\/SPAN>Parental F<\/I> = 1- (Ho <\/SUB><\/I>\/ He<\/SUB><\/I>) where: <\/SPAN><\/FONT><\/FONT> <\/SPAN>Ho<\/SUB><\/I> = observed heterozygosity, <\/FONT><\/FONT> <\/SPAN>He <\/SUB><\/I>= expected heterozygosity under Hardy-Weinberg equilibrium<\/FONT><\/FONT> The regeneration of P. malaanonan <\/I>was observed and documented. Natural stands within MFR of P. malaanonan <\/I>from the Makiling Botanic Gardens (200m asl) to the area beyond the Mudspring with an elevation of about 400-450 m asl were surveyed to gather data on natural regeneration of the species. The growth and survival of 2002 regenerants in the forest reserve was particularly monitored from 2002 to 2005. The regenerants from the recent seed production, July-August 2005, were also monitored for growth and survival. The number of surviving regenerants in the reserve was determined through time and compared with survival of those raised in the nursery. <\/FONT> <\/FONT> The most appropriate conservation approach and strategy for the species’ population in the MFR was determined based on the following criteria: genetic diversity of the species, mating system and regeneration characteristic, biophysical characteristics of the forest reserve, socioeconomic and institutional considerations. The latter three criteria were assessed using information from available documents and first hand information of the authors.<\/FONT> <\/FONT> <\/FONT> Results<\/FONT><\/FONT><\/B> <\/FONT><\/B> P. malaanonan<\/SPAN>’s outcrossing rate estimate and observed heterozygosity, Ho<\/SUB><\/I><\/FONT><\/FONT> Table 1 lists the <\/SPAN>outcrossing rate estimates and observed heterozygosity of P. malaanonan<\/I> population <\/I><\/SPAN>in Mt. Makiling. The data show the direct relation of the two values, the higher the outcrossing rate estimates, the higher the heterozygosity values. The average heterozygosity was 0.440±0.08. <\/FONT> <\/FONT> Coefficients of inbreeding, F, of adult and filial populations of <\/I>P. malaanonan<\/I><\/FONT><\/FONT> Table 2,<\/SPAN> on the other hand, shows the inbreeding coefficients, F<\/I>, of the progenies (filial), maternal\/parental and adult trees of the population in Mt. Makiling. The coefficients of inbreeding of filial populations (progenies) were for 13 families of P. malaanonan<\/I>, the same families s<\/SPAN>ampled for the mating system study of Lapitan and Hyun (2005). The coefficients of inbreeding of the mother trees and the progenies (Fe<\/SUB><\/I>) were compared following the work of Murawski et al. <\/I>(1994a), to elucidate the importance of mating system versus other influences (e.g. selection, migration and genetic drift) in determining the adult genotypic frequencies. The F <\/I>value of the parents was –0.200 indicating an excess of heterozygotes while that of the progenies (pooled) was 0.010, which means there was a very small excess of homozygotes among the progenies. <\/FONT><\/FONT> <\/FONT> Growth and survival through time of regenerants of<\/SPAN><\/I> P. malaanonan <\/SPAN><\/FONT><\/FONT> P. malaanonan <\/I><\/SPAN>is widespread in Mt. Makiling. Stands surveyed indicate the occurrence of natural regeneration dating back to several decades past. Mature trees, saplings and seedlings were found within 30 m radius of 70-100 cm diameter trees (Figure 1). <\/FONT><\/FONT> <\/FONT> The growth and survival of regenerants both in the field (Figure 2) and in the nursery (Figure 3) declined through time with those in the field declining more than those in the nursery. Lapitan and Hyun (2005) had reported a loss of about 80 seedlings\/m2<\/SUP> directly under the canopies of mother trees from 90\/m2<\/SUP> to 10\/m2<\/SUP> after the first year. Gauging from the density of trees in the stands visited, the number of seedlings that usually survive to adulthood is less than 1\/m2<\/SUP>. <\/FONT><\/p>\n","protected":false},"excerpt":{"rendered":" The genetic diversity of P. malaanonan was previously assessed from isozyme analysis of 61 individuals spread in two elevational sites within Mt. Makiling Forest Reserve (MFR) to identify conservation strategies for the population in this forest. The genetic diversity as indicated by observed heterozygosity (Ho) was found to be directly proportional to the species outcrossing rate. Comparison of F values of the adult (-0.200 to 0.068) and filial population (0.010) revealed that selection in favour of heterozygotes occurred in the population. The number of seedlings surviving from a given crop decreased through time. Considering this information, the most appropriate and cost-effective conservation strategy for the species is the immediate in situ conservation of P. malaanonan in the MFR. P. malaanonans resources in the area are well protected and are accessible therefore interventions for enhanced reproductive efficiency and effective conservation of the species is technically possible and economically feasible. The recommended interventions are: 1) rescue of randomly selected seedlings to increase survival of progenies and increase further the level of diversity in the area, 2) active management for enhanced seed production and reproductive success of selected mother trees and their use as seed sources for enrichment planting in the reserve and for future plantation establishment in other areas, and 3) protection from Swietenia macrophylla, which is reported to have become an invasive species in Mt. Makiling. <\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[7],"tags":[],"_links":{"self":[{"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/posts\/291"}],"collection":[{"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/comments?post=291"}],"version-history":[{"count":1,"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/posts\/291\/revisions"}],"predecessor-version":[{"id":1658,"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/posts\/291\/revisions\/1658"}],"wp:attachment":[{"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/media?parent=291"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/categories?post=291"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vafs.gov.vn\/en\/wp-json\/wp\/v2\/tags?post=291"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\nMaterials and methods <\/FONT><\/H2>
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n
\n