Drought, fire and tree survival in a Borneo rain forest, East Kalimantan, Indonesia
Drought, fire and tree survival in a Borneo rain forest, East Kalimantan, Indonesia
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DOI：
10.1111/j.1365-2745.2004.00954.x
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发表时间：
2005-02
影响因子：
5.5
通讯作者：
M. V. van Nieuwstadt;D. Sheil
中科院分区：
文献类型：
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作者：
M. V. van Nieuwstadt;D. Sheil
干旱和火灾越来越被认为是热带雨林动态的重要组成部分，但对此类事件的详细大规模评估很少。在这里，我们研究树木死亡率在一个低地热带雨林在东加里曼丹极端干旱后（最严重的热带森林研究报告），并随后火灾。18个1.8公顷的成对永久地块穿过防火带，使我们能够检查这两个事件的单独影响。2干旱后8个月，未烧林的树干死亡率达到18.5 ± 5.6%（平均值± SD ≥ 10 cm径级胸径，d.b.h.）。21个月后，这增加到26.3 ± 5.0%。较大茎的死亡率较高，> 80 cm d.b.h.茎的死亡率为46.6 ± 18.7%，10-20 cm直径的茎中，则为23.9 ± 3.7%。（21个月后）。被烧毁的森林显示总死亡率为64.2 ± 12.2%。21个月后增加至79.0 ± 10.2%。3通过从每个样地对中的火灾死亡率中减去单独干旱后的死亡率，我们可以估计干旱和随后的火灾的不同影响。火灾造成个体接近完全死亡70厘米直径。4.干旱造成了21个月后在被烧毁的森林中观察到的大约30%的树干死亡，但估计对死断面积和生物量的贡献分别为52%和63%。在干旱之前，森林中含有约7.3吨公顷（± 2.2，95%置信度）的地上生物量，作为死亡树木（≥ 10 cm d.b.h），仅在干旱后21个月上升到133 ± 30吨公顷，207 ± 50吨公顷。5株真铁木在干旱中存活，21个月后死亡率仅为5%。总体而言，每种死亡率与木材密度呈负相关，尽管死亡率为64%的Koompassia malaccensis是一个离群值。[6]虽然在被烧毁的森林中，物种特异性死亡率从11%到91%不等，但火灾后的总体树干存活率与较大尺寸的树皮厚度显著相关。因此，物种以及代表在大尺寸，主要是龙脑香科，增加相对优势相比，较小的类群。棕榈死亡率很低，干旱后仅为3%，烧毁的森林为10%。7.这项研究中记录的树干死亡率是在雨林中观察到的最严重的死亡率之一。这种干旱虽然罕见，但却是森林结构和组成的有力决定因素。干旱和火灾是一种特别具有破坏性的组合，因为它们分别作用于较大和较小的茎。
1 Droughts and fires are increasingly recognized as a significant component of tropical rain forest dynamics but detailed large‐scale assessments of such events are scarce. Here we examine tree mortality in a lowland rainforest in East Kalimantan after an extreme drought (the most severe ever reported in a tropical forest study), and a subsequent fire. Eighteen 1.8‐ha paired permanent plots that crossed a firebreak allowed us to examine the separate effects of the two events. 2 Eight months after the drought, stem mortality in unburned forests reached 18.5 ± 5.6% (average ± SD ≥ 10 cm diameter breast height, d.b.h.). After 21 months, this increased to 26.3 ± 5.0%. Mortality was higher in larger stems, being 46.6 ± 18.7% in stems > 80 cm d.b.h., but falling to 23.9 ± 3.7% in stems 10–20 cm d.b.h. (after 21 months). The burned forest showed an overall mortality of 64.2 ± 12.2%. This increased to 79.0 ± 10.2% after 21 months. 3 By subtracting mortality after drought alone from mortality with fire in each plot pair, we can estimate the distinct influence of drought and subsequent fire. Fire caused near complete mortality for individuals 70 cm d.b.h. 4 Drought contributes approximately 30% of the stem death observed in the burned forest after 21 months but the estimated contributions to dead basal area and biomass are higher at 52% and 63%, respectively. The forest contained around 7.3 tonnes ha−1 (± 2.2, 95% confidence) of above‐ground biomass as dead trees (≥ 10 cm d.b.h) prior to the drought, rising to 133 ± 30 tonnes ha−1 21 months after drought alone, and 207 ± 50 tonnes ha−1 in burned forest. 5 Eusideroxylon zwageri survived the drought with only 5% mortality after 21 months. Overall per‐species mortality appears negatively correlated to wood density, though Koompassia malaccensis, with 64% mortality, is an outlier. 6 Though species‐specific mortality varied from 11 to 91% in burned forest, overall stem survival after fire was significantly correlated with greater bark thickness at larger sizes. Consequently, species well represented at large sizes, mainly Dipterocarpaceae, increase in relative dominance compared with smaller taxa. Palm mortality was low, reaching only 3% after drought and 10% in burned forest. 7 The stem mortalities recorded in this study are amongst the most severe ever observed in rainforest. Such droughts, though rare, are potent determinants of forest structure and composition. Drought and fire are an especially destructive combination as they act on larger and smaller stems, respectively.