Study on the influence of fire and simultaneous bamboo flowering on the regeneration and maintenance of tropical seasonal forests in Thailand

以热带季节性森林为研究对象，结合干旱和火灾的影响，对不同光照条件下幼苗的存活和生长进行了实验研究。在林隙和封闭林冠下种植了6种乔木，分别是：龙心木（diterocarpus alatus）、刺桐木（d.p arbinatus）、狐尾木（Shorea siamensis）、大胡桃木（Pterocarpus macrocarpus）、木香木（Xylia xylocarpa var. kerrii）和大叶木（Sterculia macrophylla）。对于每种光照条件，我们采用三种处理：旱季连续浇水(W)，旱季地面生火(F)，不浇水/不生火（完整，I）。所有树种的存活率和生长率在林隙中均高于封闭林冠下，其中以siamensis和p.a macrocarpus的存活率和生长率最高。在密闭林冠下，两种植物的存活率均较高，旱季浇水显著提高了两种植物的存活率。在旱季浇水导致五种植物的生长速率更高。火处理后，天麻和刺青的幼苗均不能再发芽而死亡。旱季和火处理后，林隙内生长的柽柳、大竹叶、木杉和大竹叶幼苗的成活率均高于树荫下。这些树种在林隙中的幼苗比封闭林冠下的幼苗分配到地下部分的比例更高，这可能支持了火灾后发芽的能力。雨季的光照条件极大地影响了旱季幼苗的存活和抗火性，我们的研究结果表明，不同物种的幼苗在适应遮荫、干旱和火方面存在差异。1998年和2001年，大球藻（Gigantchloa albociliata）和大球藻（Cephalostacyum pergracile）同时开花。花期后几乎所有的竹团都死亡了，而被抑制的竹团在花期后不开花并存活了下来。竹团死亡后，出现了许多竹团，并且生长迅速。这表明这些竹种可以在树荫下维持树苗库，而树荫下的个体在开花事件中可能表现不同。竹子的同时死亡与树木和竹子的再生过程之间的关系不是一个简单的故事，需要进一步研究。少

Seedling survival and growth under contrasting light conditions were experimentally studied in combination with the effects of the drought and fire in a tropical seasonal forest. Seedlings of six tree species, Dipterocarpus alatus, D.turbinatus, Shorea siamensis, Pterocarpus macrocarpus, Xylia xylocarpa var. kerrii, and Sterculia macrophylla, were planted in a gap and under the closed canopy. For each light condition, we applied three treatments : continuous watering during the dry season (W), ground fire during the dry season (F), and no watering/no fire (intact, I). Survival and growth rate were greater in the gap than under the closed canopy for all species, most dramatically for S.siamensis and P.macrocarpus. Dipterocarpus alatus and D.turbinatus had relatively high survival under the closed canopy, and watering during the dry season resulted in significantly higher survival rate for these two species. Watering during the dry season resulted in the higher growth rate for five speci … More es. All seedlings of D.alatus and D.turbinatus, failed to resprout and died after fire. The survival rate during the dry season and after the fire treatment was higher for the seedlings grown in the canopy gap than in the shade for S.siamensis, P.macrocarpus, X.xylocarpa var.kerrii, and S.macrophylla. The seedlings of these species in the canopy gap had higher allocation to the belowground parts than those under the closed canopy, which may support ability to sprout after fire. The light conditions during the rainy season greatly affect seedling survival and resistance to fire during the subsequent dry season, and our results suggest differentiation among species in terms of seedling adaptations to shade, drought and fire.Synchronized flowering of the Gigantchloa albociliata and Cephalostacyum pergracile occurred simultaneously in 1998 and 2001, respectively. Almost all of the clumps died after the flowering, but the suppressed clumps did not flower and survived after the flowering event in case of G.albociliata, After the death of G.albociliata clumps, many clumps of Bambusa tulda emerged and stated to grow quickly. These suggest that these bamboo species can maintain sapling banks under the shade, and shaded individuals may behave differently at the flowering event. The relationship between the simultaneous death of bamboo and the regeneration process of trees and bamboos is not a simple story and need further investigation. Less