Genetic assessment of three Fagaceae species in forest restoration trials

Abstract

Restoring isolated patches of forest ecosystems in degraded landscapes could potentially lead to genetic loss and inbreeding. Therefore, this study determined the occurrence of genetic diversity among the tree species Castanopsis tribuloides, C. calathiformis, and Lithocarpus polystachyus all of which were proven previously to be effective native tree species in the restoration of upland evergreen forests in northern Thailand when using the seed sample collection method. We tested our hypothesis as to whether the genetic diversity of a plant population that had been planted from the seeds of 4–6 adult trees would be lower and whether incidences of fixation index (Fis) would be higher among the second generation seedlings of these three Fagaceae species in isolated forest restoration trial plots. Microsatellite primers were selected from the entire genome sequence of C. tribuloides and the genetic sequences of C. tribuloides, L. polystachyus, and C. calathiformis were analyzed. Our results indicated a high degree of genetic diversity (He) in C. tribuloides (0.736) and C. calathiformis (0.481); however, a low level of genetic diversity was observed in L. polystachyus (0.281) within the restored forest. The fixation index for the second generation of L. polystachyus and C. calathiformis in the restored forest showed evidence of inbreeding. These results imply the efficiency of the seed sample collection method and verify that it does not reduce the level of genetic diversity in C. tribuloides and C. calathiformis. However, it may result in incidences of an inbreeding phenomena, suggesting the need to increase the number of adult trees used at the seed collection stage.

Collaboration and Conflict—Developing Forest Restoration Techniques for Northern Thailand’s Upper Watersheds Whilst Meeting the Needs of Science and Communities

“…The recovery of biodiversity and carbon accumulation were assessed by CMU graduate students for their thesis projects, by comparing among framework species trial plots of various ages, non-planted control plots (undergoing natural regeneration) and nearest mature forest (Pah Dong Saeng). Biodiversity studies have investigated species richness, diversity and the community composition of birds, mammals, ground flora, soil microbes, lichens and bryophytes [7][8][9][10], as well as the maintenance of genetic diversity across generations within some of the framework species planted [11][12][13]. Carbon studies have covered litter fall, soil carbon, and above-ground carbon in trees [14][15][16].…”

“…That is no longer true for EGF in northern Thailand and for other forest types where a similar approach has been applied. Research at the BMS site established (1) which species to plant [19,20], (2) optimum seed-collection times and techniques [11,13,18], (3) optimum treatments for seed storage [21] and germination [17], (4) time and treatments needed to grow saplings to optimum size by the optimum planting time [18,[22][23][24][25][26], (5) optimum planting techniques and spacing [7,20], (6) optimum fertilizer regimes [4] and weeding methods and frequency [17], (7) how fast biodiversity returns [7,9,10] and (8) how much carbon forest restoration can sequester [14][15][16] Through the project's education and outreach activities and its publications, this substantial body of knowledge has been used to improve forest restoration practices throughout SE Asia (e.g., [1,27]).…”