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Puangpaka Kaewkrom Jiragorn Gajaseni Carl F. Jordan Nantana Gajaseni 《Forest Ecology and Management》2005,210(1-3):351-361
Teak is the most important timber species in northern Thailand, and as such, large areas of teak forest have been disturbed or become highly degraded. Teak plantations have been established on this highly degraded land, where the rate of natural recovery is relatively slow. At the study site, five mixed or pure teak plantation types have been established to ameliorate limiting soil properties in order that long-term productivity is maintained. Observations within these plantations in northern Thailand have suggested that native species become established naturally under the shade of a “nurse” plantation, one that shades out early successional species. The objective of this study was to investigate the influence of the number of species in nurse plantations on the diversity and number of seedlings representative of mature native forests that become established within the plantations. Five types of plantations were investigated: (1) Tectona grandis L.f. (T); (2) T.grandis and Tamarindus indica L. (TT); (3) T.grandis and Gmelina arborea Roxb. (TG); (4) T.grandis, T. indica and G. arborea (TTG); (5) T.grandis, T.indica and Anacardium occidentale L. (TTA). These plantations were established primarily for the production of T.grandis (teak), with the other species introduced as economic trees. The plantations were surrounded by native stands of species representative of late successional and mature teak forests. In each of the plantations studies measurements were made on species density, species diversity, and evenness of plants regenerating in the understorey. Results showed that plantations consisting of several species in the overstorey had a higher diversity of native forest species in the understorey than the single-species plantation. Mixed plantation types were also found to reduce the density of the grass Imperata cylindrica (L.) P. Beauv. Consideration of the establishment of woody species found that TG and TTA had high densities of trees and shrubs. This suggested that if the goal of management was to regenerate forest with a high diversity of tree species similar to that found in native mature forests, multiple-species plantations, especially TG and TTA, would be more effective nurse communities than the single-species plantation in providing an environment into which seeds of native species could disperse and germinate. In addition, several climax species, such as Xylia xylocarpa (Roxb.) Taub. var. kerrii (Craib & Hutch) I.C. Nielsen, Pterocarpus macrocarpus Kurz, Largerstroemia sp., Afzelia xylocarpa (Kurz) Craib, Lannea coromandelica (Houtt) Merr., Spondias pinnata (L.f.) Kurz, Garuya pinnata Roxb., Terminalia mucronata Craib & Hutchison, Diospyoros mollis Griff., Irvingia malayana Oliv. ex Benn., Milletia leucantha Kurz, Dalbergia oliviri Gamble ex Prain, Chukrasia tabularis A. Juss and Schleichera oleosa (Lour.) Oken, were found in the early stages of succession, thus indicating that some may be suitable for planting in future restoration processes in order to accelerate natural succession and provide economic returns to managers. 相似文献
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Although the homegarden systems in the tropics are claimed to sustain basic community needs without environmental deterioration,
the ecological rationalities behind the harmony between the humans, homegardens, and the environment are not well understood.
Four study sites (Sukhothai, Srisatchanalai, Ayudhaya, and Nonthaburi) representing the four Thai eras in the Chao Phraya
Basin were selected for studying these rationalities. The size and physical stature of the homegardens, their plant association
and community features, physical environmental factors, nutrient and soil fertility parameters, and cultivation practices
were studied. The major factor that determines species selection in homegardens is the utilization of the products, while
the various practices within the homegardens are determined by such factors as the species, the system, and the environment.
All homegardens had four vertical stratifications, with physical structures almost similar to that of dry dipterocarp forest,
but with lower height for each layer, lower diversity of plants, and sparser crown layer. The analysis also shows a high possible
utilization efficiency for space, light, water and nutrients in the soil in the homegardens. Shannon-Wiener's indices of species
diversity of the homegardens were close to those of dipterocarp forest. The homegardens are in-situ reservoirs for biodiversity
at genetic-, species-, and ecological levels. There was no complete harvesting from these homegardens. This practice ensured
minimal nutrient export from the systems, while high amounts and diversity of litter biomass should contribute to high efficiency
of nutrient cycling. Futhermore, phosphorus availability could be better in homegardens. The homegardens had more favorable
microenvironment with lower soil and atmospheric temperature and higher relative humidity than outside. There has been no
single incident of a pest outbreak at a threatening level.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Profiles of carbon stocks in forest, reforestation and agricultural land, Northern Thailand 总被引：1，自引：0，他引：1
A study was conducted to assess carbon stocks in various forms and land-use types and reliably estimate the impact of land use on C stocks in the Nam Yao sub-watershed (19°05'10"N, 100°37'02"E), Thailand. The carbon stocks of aboveground, soil organic and fine root within primary forest, reforestation and agricultural land were estimated through field data collection. Results revealed that the amount of total carbon stock of forests (357.62 ± 28.51 Mg·ha-1, simplified expression of Mg (carbon)·ha-1) was significantly greater (P＜ 0.05) than the reforestation (195.25 ±14.38 Mg·ha-1) and the agricultural land (103.10±18.24 Mg·ha-1). Soil organic carbon in the forests (196.24 ±22.81 Mg·ha-1) was also significantly greater (P＜ 0.05) than the reforestation (146.83± 7.22 Mg·ha-1) and the agricultural land (95.09 ± 14.18 Mg·ha-1). The differences in carbon stocks across land-use types are the primary consequence of variations in the vegetation biomass and the soil organic matter. Fine root carbon was a small fraction of carbon stocks in all land-use types. Most of the soil organic carbon and fine root carbon content was found in the upper 40-cm layer and decreased with soil depth. The aboveground carbon(soil organic carbon: fine root carbon ratios (ABGC: SOC: FRC), was 5:8:1, 2:8:1, and 3:50:1 for the forest, reforestation and agricultural land, respectively. These results indicate that a relatively large proportion of the C loss is due to forest conversion to agricultural land. However, the C can be effectively recaptured through reforestation where high levels of C are stored in biomass as carbon sinks, facilitating carbon dioxide mitigation. 相似文献
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