A new tree-ring sampling method to estimate forest productivity and its temporal variation accurately in natural forests

Xu, Kai; Wang, Xiangping; Liang, Penghong; Wu, Yulian; An, Hailong; Sun, Han; Wu, Pengcheng; Wu, Xian; Li, Qiaoyan; Guo, Xin; Wen, Xin; Wei, Han; Liu, Chao; Fan, Dayong

doi:10.1016/j.foreco.2018.10.066

Cited by 23 publications

(12 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Tree growth indicators from tree rings are good proxies for forest productivity in humid forests (Xu et al, 2019), and our findings suggest that the presence of a shallow water table and groundwater use by sandy humid forests substantially increases forest productivity. In areas of shallow groundwater (DTG < 2.5 m), we observed consistently higher tree growth in P. resinosa trees than trees in areas of deeper groundwater (DTG > 3 m) for the past 88 years (Figure 5).…”

Section: Discussionsupporting

confidence: 59%

Groundwater subsidizes tree growth and transpiration in sandy humid forests

Ciruzzi

Loheide

2021

Ecohydrology

View full text Add to dashboard Cite

As drought variability increases in forests around the globe, it is critical to evaluate and understand ecosystem attributes that ameliorate drought impacts. Trees in arid and semi‐arid ecosystems can sustain tree growth and transpiration during drought by accessing shallow groundwater, yet the extent to which groundwater influences forest growth and transpiration in humid environments has largely been unexplored. We quantified groundwater's influence on tree growth and transpiration in northern humid forests with sandy soils. We hypothesized that even in wet regions, soil droughts occur relatively frequently in forests with sandy soils and result in water stress and reduced tree growth. Further, we hypothesized these reductions in productivity are ameliorated if the forest can access shallow groundwater during dry conditions. We evaluated tree growth responses using tree cores in Pinus resinosa trees and estimated forest groundwater use from diel water table fluctuations across sites covering a 1‐ to 9‐m depth‐to‐groundwater (DTG) gradient. In areas of shallow groundwater (DTG < 2.5 m), we observed twice as much tree growth and high, frequent groundwater use (up to 81% of non‐rainy summer days). Groundwater's influence on tree growth and transpiration declined as groundwater deepened along the DTG gradient in the range 1–5 m below land surface. These findings suggest that water provided by a shallow water table subsidizes evapotranspiration in humid forests and results in enhanced tree growth. Our research provides a basis for understanding the role of groundwater in conferring drought resistance in humid forests to help guide sustainable water and forest management decisions.

show abstract

Section: Discussionsupporting

confidence: 59%

Groundwater subsidizes tree growth and transpiration in sandy humid forests

Ciruzzi

Loheide

2021

Ecohydrology

View full text Add to dashboard Cite

show abstract

“…However, satellites or aerial scanning data can only assess biomass dynamics of the last decades and the current changes in anthropogenic pressure might have slightly biased the obtained results. Currently, only some studies have investigated centennial trends in aboveground biomass as a result of changing environmental conditions based on direct field observations (Clark et al 2001;Babst et al 2014;Grafius and Malanson 2015;Moiseev et al 2016;Liu et al 2016;Xu et al 2019) and analyzing tree-ring data (Graumlich et al 1989;Dye et al 2016), making it difficult to quantify current trends in the carbon sequestration and productivity of terrestrial ecosystems.…”

Section: Introductionmentioning

confidence: 99%

Climate change evidence in tree growth and stand productivity at the upper treeline ecotone in the Polar Ural Mountains

et al. 2020

View full text Add to dashboard Cite

Background: Recent warming is affecting species composition and species areal distribution of many regions. However, although most treeline studies have estimated the rates of forest expansion into tundra, still little is known about the long-term dynamic of stand productivity at the forest-tundra intersection. Here, we make use of tree-ring data from 350 larch (Larix sibirica Ledeb.) and spruce (Picea obovata Ledeb.) sampled along the singular altitudinal treeline ecotone at the Polar Urals to assess the dynamic of stand establishment and productivity, and link the results with meteorological observations to identify the main environmental drivers. Results: The analysis of stand instalment indicated that more than 90% of the living trees appeared after 1900. During this period, the stand became denser and moved 50 m upward, while in recent decades the trees of both species grew faster. The maximum afforestation occurred in the last decades of the twentieth century, and the large number of encountered saplings indicates that the forest is still expanding. The upward shift coincided with a slight increase of May-August and nearly doubling of September-April precipitation while the increase in growth matched with an early growth season warming (June + 0.27°C per decade since 1901). This increase in radial growth combined with the stand densification led to a 6-90 times increase of biomass since 1950. Conclusion: Tree-ring based twentieth century reconstruction at the treeline ecotone shows an ongoing forest densification and expansion accompanied by an increased growth. These changes are driven by climate change mechanism, whereby the leading factors are the significant increase in May-June temperatures and precipitation during the dormant period. Exploring of phytomass accumulation mechanisms within treeline ecotone is valuable for improving our understanding of carbon dynamics and the overall climate balance in current treeline ecosystems and for predicting how these will be altered by global change.

show abstract

“…In contrast to the studies assuming reduced white spruce growth under warmer and drier climate, Sullivan et al (2017) reported only limited evidence for such a negative growth trend. While they applied state of the art data "detrending" ["signal-free methodology, " (Melvin andBriffa, 2008, 2014)], uncertainties still remain because of potentially huge sample biases (Duchesne et al, 2019), which even the best data processing cannot yet quantify: Even when selecting a representative sample of trees in a population at one point in time (Nehrbass-Ahles et al, 2014;Xu et al, 2019), growth trends could still be biased. This is because fast growing trees typically die at a younger age.…”

Section: Controversies Around Growth Trendsmentioning

confidence: 99%

“…In dendrochronology, the effect of biases caused by the tree-selection method within a site have been explored by Nehrbass-Ahles et al (2014), who argued that either all trees or a random selection of trees should be sampled. Xu et al (2019) explored in more detail how many trees of which size class have to be selected to minimize sampling effort and still derive a representative sample set. However, even when coring all trees in a forest stand, the sample will not necessarily be representative in the decades prior to sampling the cores.…”

Section: How Representative Is the Sample?mentioning

confidence: 99%

A Unifying Concept for Growth Trends of Trees and Forests – The “Potential Natural Forest”

Trouillier

Maaten‐Theunissen

Scharnweber

et al. 2020

Front. For. Glob. Change

View full text Add to dashboard Cite

Changes in the environment will alter the growth rate of trees and forests. Different disciplines assess such growth rates differently, for example, with tree-ring width data, forest inventories or with carbon-flux data from eddy covariance towers. Such data is used to quantify forests biomass increment, forest's carbon sequestration or to reconstruct environmental variables before instrumental records. However, raw measurement data is typically not considered to be representative for the average growth rate of trees or forests. Depending on the research question, the effects of certain environmental variables or effects of tree and forest structure have to be removed first. It can be challenging to define and quantify a growth trend that can answer a specific research question because trees and forests grow and respond to environmental change in multiple ways simultaneously, for example, with altered radial increment, height growth, and stand density. Further challenges pose time-lagged feedback loops, for example, between height and radial increment or between stand density and radial increment. Generally, different environments will lead to different tree and forest structures, but because of tree's longevity this adaptation to the new environment will take decades or even centuries. Consequently, there can be an offset between the present forest structure and what we term the potential natural forest (PNF): Similar to the potential natural vegetation (PNV), the PNF represents that forest that would develop under the current environmental conditions in the absence of human intervention. Because growth rates are affected by the tree and forest structure, growthtrend estimates will differ between the present and the potential forest. Consequently, if the legacy effects of the past are not of interest, the PNF is the theoretical baseline to correct and estimate growth trends.

show abstract

A new tree-ring sampling method to estimate forest productivity and its temporal variation accurately in natural forests

Cited by 23 publications

References 41 publications

Groundwater subsidizes tree growth and transpiration in sandy humid forests

Groundwater subsidizes tree growth and transpiration in sandy humid forests

Climate change evidence in tree growth and stand productivity at the upper treeline ecotone in the Polar Ural Mountains

A Unifying Concept for Growth Trends of Trees and Forests – The “Potential Natural Forest”

Contact Info

Product

Resources

About