Differences in seasonality and temperature dependency of stand transpiration and canopy conductance between Japanese cypress (Hinoki) and Japanese cedar (Sugi) in a plantation
Differences in seasonality and temperature dependency of stand transpiration and canopy conductance between Japanese cypress (Hinoki) and Japanese cedar (Sugi) in a plantation
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DOI：
10.1002/hyp.11162
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发表时间：
2017-05-15
影响因子：
3.2
通讯作者：
Giambelluca, Thomas W.
中科院分区：
文献类型：
--
作者：
Saito, Takami;Kumagai, Tomo'omi;Giambelluca, Thomas W.
在本文中，我们对日本两种最常见的人工林树种蒸腾作用的种间差异进行了调查，这两种树种均属于柏科，具有不同的本地分布北部界限，即日本柏树（Hinoki; Chamaecyparis obtusa Sieb. et Zucc.）和日本雪松（Sugi; Cryptomeria japonica D. Don）。在 42 年种植园内的 2 个附近叶面积指数相似的林分中测量了茎液流量。在理想的秋季环境中观察到单树和林分尺度的蒸腾速率（分别为 E-tre 和 E-sta）。在林分尺度上，扁柏的平均树液通量密度大于杉树，而单位面积边材总面积则小于杉树。由于这两个变量对蒸腾作用具有平衡作用，因此扁柏的 E-sta 与杉木的 E-sta 相似（94%）。在这两个物种的平均 E-tre 之间也发现了这种偏移。 5月至10月各林分的E-sta相似，而2月至4月杉木的E-sta明显大于Hinoki。这3个月内，累积E-sta差异为21.7毫米，占Hinoki和Sugi年E-sta差异（分别为192和219mm/年）的79%。我们发现杉树的冠层导度（G(c)）及其对白天平均水汽压不足的敏感性在早春特别高，而桧木的冠层导度在整个生长季节逐渐变化。这种差异与杉树的G(c)最适温度有关，其比扁柏的G(c)最适温度低约10℃。我们的研究结果表明，节水树种（例如扁柏）的种植园木材生产缓慢，但水资源丰富。此外，对于像杉树这样对高温敏感的树木的种植园，管理者应该担心预期的全球变暖可能导致未来的衰退。
In this paper, we present an investigation of interspecies differences in transpiration of the 2 most common plantation forest tree species in Japan, both in the family Cupressaceae with different northern limits of native distribution, Japanese cypress (Hinoki; Chamaecyparis obtusa Sieb. et Zucc.) and Japanese cedar (Sugi; Cryptomeria japonica D. Don). The stem sap flow rate was measured in 2 nearby stands of similar leaf area index in a 42-year-old plantation. Single-tree and stand-scale transpiration rates (E-tre and E-sta, respectively) were observed during an ideal autumn environment. At the stand scale, mean sap flux density of Hinoki was greater than that of Sugi, whereas total sapwood area per ground area was smaller in Hinoki than Sugi. Because the 2 variables had counterbalancing effects on transpiration, E-sta of Hinoki was similar to (94% of) that of Sugi. This offset was also found between the mean E-tre of the 2 species. E-sta was similar between the stands from May to October, whereas E-sta of Sugi was notably greater than that of Hinoki from February to April. During these 3months, the difference in cumulative E-sta was 21.7mm, which accounted for 79% of the difference in annual E-sta between Hinoki and Sugi (192 and 219mm/year, respectively). We found that canopy conductance (G(c)) and its sensitivity to the mean vapour pressure deficit during daylight hours in Sugi were particularly high in early spring, whereas those in Hinoki shifted gradually throughout the growing season. This difference was related to the optimal temperature of G(c) in Sugi, which was approximately 10 degrees C lower than that in Hinoki. Our results suggest that plantations of water-conserving species such as Hinoki produce timber slowly but yield water resources generously. Moreover, for plantations of trees sensitive to high temperature, such as Sugi, managers should be concerned about possible future decline caused by anticipated global warming.