Paired analysis of tree ring width and carbon isotopes indicates when controls on tropical tree growth change from light to water limitations.
Paired analysis of tree ring width and carbon isotopes indicates when controls on tropical tree growth change from light to water limitations.
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DOI：
10.1093/treephys/tpab142
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发表时间：
2022-06-09
期刊：
影响因子：
4
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中科院分区：
文献类型：
--
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光和水的可获得性可能会随着封闭树冠林木的寿命而变化，林下树木因光的生长受到更大的限制，而树冠树由于干旱而受到更大的限制。由于干旱和遮荫对同位素识别(Δ13C)有相反的影响，配对测量年轮宽度和Δ13C可能被用来区分水分和光照对树木生长的限制。我们在玻利维亚和墨西哥的三个热带森林中测试了这种方法，这些森林的降雨量和树冠结构不同。使用年轮宽度和Δ13C数据，我们评估了从林下到树冠对树木生长的控制是如何变化的。生长和Δ13C在林下大部分是反相关的，但当树木到达树冠时，这种反相关消失或减弱，特别是在最潮湿的地方。这表明由于光照水平的变化，林下生长的变化受光合作用碳同化的控制。当树木到达冠层时，生长的年际变化与其中一个干旱部位的Δ13C呈正相关，表明生长的年际变化是由影响气孔导度的水分胁迫的变化驱动的。对年轮宽度和碳同位素的配对分析提供了重要的洞察，即什么环境因素控制了树木的生长；封闭式潮湿森林中林下树木的强光限制转变为干旱胁迫，而干燥森林中的(亚)冠层树木则受到干旱胁迫。我们表明，结合同位素和年轮宽度测量可以显著改善我们对树木功能的洞察，并可用于区分由于遮荫而造成的限制和由于干旱造成的限制。
Light and water availability are likely to vary over the lifespan of closed-canopy forest trees, with understory trees experiencing greater limitations to growth by light and canopy trees greater limitation due to drought. As drought and shade have opposing effects on isotope discrimination (Δ13C), paired measurement of ring width and Δ13C can potentially be used to differentiate between water and light limitations on tree growth. We tested this approach for Cedrela trees from three tropical forests in Bolivia and Mexico that differ in rainfall and canopy structure. Using lifetime ring width and Δ13C data for trees of up to and over 200 years old, we assessed how controls on tree growth changed from understory to the canopy. Growth and Δ13C are mostly anti-correlated in the understory, but this anti-correlation disappeared or weakened when trees reached the canopy, especially at the wettest site. This indicates that understory growth variation is controlled by photosynthetic carbon assimilation due to variation in light levels. Once trees reached the canopy, inter-annual variation in growth and Δ13C at one of the dry sites showed positive correlations, indicating that inter-annual variation in growth is driven by variation in water stress affecting stomatal conductance. Paired analysis of ring widths and carbon isotopes provides significant insight in what environmental factors control growth over a tree’s life; strong light limitations for understory trees in closed-canopy moist forests switched to drought stress for (sub)canopy trees in dry forests. We show that combined isotope and ring width measurements can significantly improve our insights in tree functioning and be used to disentangle limitations due to shade from those due to drought.
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影响因子：
5.5
作者：
Brum, Mauro;Vadeboncoeur, Matthew A.;Oliveira, Rafael S.
通讯作者：
Oliveira, Rafael S.
影响因子：
2.7
作者：
Buchmann, N;Guehl, JM;Ehleringer, JR
通讯作者：
Ehleringer, JR
影响因子：
30.7
作者：
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通讯作者：
Shaw, John
DOI：
10.1111/j.1600-0889.2008.00370.x
发表时间：
2008-11-01
影响因子：
2.3
作者：
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通讯作者：
Schleser, Gerhard H.
影响因子：
2.3
作者：
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通讯作者：
Hietz, Peter