Detecting invisible growth rings of trees in seasonally dry forests in Thailand: isotopic and wood anatomical approaches
Detecting invisible growth rings of trees in seasonally dry forests in Thailand: isotopic and wood anatomical approaches
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DOI：
10.1007/s00468-009-0322-3
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发表时间：
2009-08-01
影响因子：
2.3
通讯作者：
Veenin, Teera
中科院分区：
文献类型：
--
作者：
Ohashi, Shinta;Okada, Naoki;Veenin, Teera
我们测量了径向变化的碳同位素组成和船只性状的树种在泰国东北部的季节性干燥的森林，探索一个更可靠的和经得起考验的方法，缺乏视觉上可检测和一致的年轮树木的热带树木年轮。对6种生长轮不明显或不规则的龙脑香科植物（3种Shorea、2种Dipterocarpus和1种Hopea）和柚木（Tectona grandis）进行了研究。所有物种的δ C-13值变化都具有明显的年周期性。龙脑香科植物的δ C-13值通常在生长季中期最低，而柚木的δ C-13值在生长季末期最低。由于研究物种的生长季节几乎对应于研究区的雨季，三角洲C-13的变化可能是由水分供应的变化引起的。柚木不同的变异模式是由于其更强的依赖于C-13丰富的储备物质在生长季节的早期。所有树种导管性状的变化也表现出年周期性。龙脑香科植物的δ C-13值与导管测量值之间存在显著的相关性。血管管腔（平均面积，切向和径向直径，总面积的比例）呈负相关，而血管频率呈正相关。相关性表明，导管性状的变化是由树木可利用水分的季节变化引起的。因此，我们的结论是，木材解剖学的方法，以及三角洲C-13，有很大的潜力作为工具，在热带树木年轮学的背景下，季节性气候。
We measured radial variation of carbon isotope composition and vessel traits in tree species in seasonally dry forests of Northeast Thailand to explore a more reliable and amenable method of tropical dendrochronology for trees that lack visually detectable and consistent growth rings. Six Dipterocarpaceae species (3 Shorea, 2 Dipterocarpus, and 1 Hopea species) with indistinct or irregular growth rings and teak (Tectona grandis), a species which forms distinct growth rings, were examined. The delta C-13 value variations in all species showed annual cyclicity. Dipterocarpaceae species usually marked the lowest values of delta C-13 in the middle of the growing season, whereas teak had the lowest values at nearly the end of the growing season. Since the growing season of the species examined almost corresponds to the rainy season in the study area, the delta C-13 variation was likely caused by the change in moisture availability. The different variation pattern of teak was attributable to its stronger dependence on C-13-enriched reserved material early in the growing season. Changes in tree vessel traits for all species examined also showed annual cyclicity. Dipterocarpaceae species showed significant correlation between delta C-13 values and vessel measurements. Vessel lumen (mean area, tangential and radial diameter, and proportion of total area) had a negative correlation, whereas vessel frequency showed a positive correlation. The correlations indicated that changes in vessel traits were caused by the seasonal variation of moisture available to the trees. Thus, we concluded that methods using wood anatomy, as well as delta C-13, have great potential for use as tools in tropical dendrochronology within the context of seasonal climate.