The 2018 drought and its consequences: Investigating the resilience of different tree species based on comprehensive long-term monitoring of forest hydrology

2020 ◽  
Author(s):  
Theresa Blume ◽  
Daniel Balanzategui ◽  
Lisa Schneider ◽  
Daniel Rasche ◽  
Markus Morgner ◽  
...  
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Water Deficit ◽  
Tree Growth ◽  
Tree Species ◽  
Temperate Forest ◽  
Subsurface Water ◽  
Forest Stands ◽  
Northeastern Germany

<p>Many forests in Central Europe experienced unprecedented drought conditions in 2018. The exceptionally long dry period, lasting from early-summer 2018 and into the winter, was followed by another dry summer with record-breaking temperatures.   Ecohydrological consequences of extended droughts for these temperate forest systems are difficult to anticipate, and investigating the resilience of forest hydrological systems requires comprehensive and systematic long-term observations.</p><p>Monitoring at the TERENO-NE temperate forest observatory in northeastern Germany includes input characterization (throughfall and stemflow), high-resolution soil moisture observations in 14 different forest stands down to a depth of 2 m below the soil surface, shallow and deep groundwater observations, sap flow, tree water deficit and high-resolution tree growth measurements since 2012. The investigated forest stands cover the three tree species pine, oak and beech in both pure and mixed stands. This is complemented by terrestrial gravimetric measurements of total water storage changes. Steep hillslope transects allow us to investigate the impact of presence or absence of groundwater availability on tree water uptake and growth.</p><p>We find that after the unprecedented drought in 2018, which already had pronounced ecohydrological effects, the rainfall amounts over the winter 2018/19 were insufficient to refill the subsurface water storages. Dry conditions altered the growth phenology of each monitored tree species, while tree-water deficit and tree growth were negatively impacted in both years, but to varying extent. Soil moisture storage and dynamics are strongly affected and the drought caused a long-term memory effect.</p>

scholarly journals Tree shape and form in ancient coppice woodlands

2017 ◽  
Vol 10 (2) ◽  
pp. 49-62 ◽  
Author(s):  
Petr Maděra ◽  
Tomáš Slach ◽  
Luboš Úradníček ◽  
Jan Lacina ◽  
Linda Černušáková ◽  
...  
Keyword(s):  
Tree Species ◽  
Field Survey ◽  
Scientific Literature ◽  
Forest Stands ◽  
Tree Shape ◽  
Lack Of Information ◽  
Basic Features

Abstract Ancient coppice woodlands are coppice-originated forest stands with a long-term continual development, and with the preserved typical natural and historic elements of old sprout forests. Prominent natural elements in the ancient coppice woodlands are namely old coppice stools. There is, in scientific literature, lack of information about features of ancient coppice stools. Therefore, our contribution aims to describe shape and form of ancient coppice stools, including the most important microhabitat of coppice woodlands – dendrothelms. Based on field survey of 20 localities of important coppice woodlands we recorded 135 ancient coppice stools of 13 tree species and a total of 80 dendrothelms in 9 tree species. Basic features of ancient coppice stools and dendrothlems were measured and evaluated.

scholarly journals Assessing the influence of climate on the growth rate of boreal tree species in northeastern Canada through long term permanent sample plot datasets

2020 ◽  
Author(s):  
Tyler Searls ◽  
Xinbiao Zhu ◽  
D.W. McKenney ◽  
Rony Mazumder ◽  
James Steenberg ◽  
...  
Keyword(s):  
Tree Growth ◽  
Tree Species ◽  
Newfoundland And Labrador ◽  
Climatic Variables ◽  
Limiting Factor ◽  
Climate Projections ◽  
Sample Plot ◽  
Permanent Sample Plot ◽  
Mixed Modelling

Climate has a considerable influence on tree growth. Forest managers benefit from the empirical study of the historic relationship between climatic variables and tree growth to support forest management frameworks which are to be applied under scenarios of climate change. Through this research, we have utilized long-term permanent sample plot records, historic climate datasets, and linear mixed modelling techniques to evaluate the historic influence of climatic variables on the growth rates of major boreal tree species in Newfoundland and Labrador, Canada. For the commercially significant spruce and fir forests of the province, we found growing degree days (GDD) to negatively correlate with tree productivity in warmer regions, such as much of Newfoundland (±1,350 GDD), but positively correlate with growth in cooler regions, such as those in Labrador (±750 GDD). With respect to precipitation, environmental moisture was not on average a limiting factor to species productivity in the province. These dynamics have implications for the productivity of the spruce-fir forests of the study area when considered alongside contemporary climate projections for the region, which generally entail both a warmer and wetter growing environment.

scholarly journals Deep desiccation of soils observed by long-term high-resolution measurements on a large inclined lysimeter

2020 ◽  
Author(s):  
Markus Merk ◽  
Nadine Goeppert ◽  
Nico Goldscheider
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Vegetation Period ◽  
Test Site ◽  
Change Point Detection ◽  
Key Factors ◽  
Moisture Fluxes ◽  
Meteorological Influences ◽  
Point Detection

Abstract. Availability of long-term and high-resolution measurements of soil moisture is crucial when it comes to understanding all sorts of changes to past soil moisture variations and the prediction of future dynamics. This is particularly true in a world struggling against climate change and its impacts on ecology and economy. Feedback mechanisms between soil moisture dynamics and meteorological influences are key factors when it comes to understanding the occurrence of drought events. We used long-term high-resolution measurements of soil moisture on a large inclined lysimeter at a test site near Karlsruhe, Germany. The measurements indicate (i) a seasonal evaporation depth of over two meters. Statistical analysis and linear regressions indicate (ii) a significant decrease in soil moisture levels over the past two decades. This decrease is most pronounced at the start and the end of the vegetation period. Furthermore, Bayesian change point detection revealed (iii), that this decrease is not uniformly distributed over the complete observation period. Largest changes occur at tipping points during years of extreme drought, with significant changes to the subsequent soil moisture levels. This change affects not only the overall trend in soil moisture, but also the seasonal dynamics. A comparison to modeled data showed (iv) that the occurrence of deep desiccation is not merely dependent on the properties of the soil but is spatially heterogeneous. The study highlights the importance of soil moisture measurements for the understanding of soil moisture fluxes in the vadose zone.

scholarly journals Deep desiccation of soils observed by long-term high-resolution measurements on a large inclined lysimeter

2021 ◽  
Vol 25 (6) ◽  
pp. 3519-3538
Author(s):  
Markus Merk ◽  
Nadine Goeppert ◽  
Nico Goldscheider
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Vegetation Period ◽  
Test Site ◽  
Change Point Detection ◽  
Key Factors ◽  
Moisture Fluxes ◽  
Meteorological Influences ◽  
Point Detection

Abstract. Availability of long-term and high-resolution measurements of soil moisture is crucial when it comes to understanding all sorts of changes to past soil moisture variations and the prediction of future dynamics. This is particularly true in a world struggling against climate change and its impacts on ecology and the economy. Feedback mechanisms between soil moisture dynamics and meteorological influences are key factors when it comes to understanding the occurrence of drought events. We used long-term high-resolution measurements of soil moisture on a large inclined lysimeter at a test site near Karlsruhe, Germany. The measurements indicate (i) a seasonal evaporation depth of over 2 m. Statistical analysis and linear regressions indicate (ii) a significant decrease in soil moisture levels over the past 2 decades. This decrease is most pronounced at the start and the end of the vegetation period. Furthermore, Bayesian change-point detection revealed (iii) that this decrease is not uniformly distributed over the complete observation period. The largest changes occur at tipping points during years of extreme drought, with significant changes to the subsequent soil moisture levels. This change affects not only the overall trend in soil moisture, but also the seasonal dynamics. A comparison to modeled data showed (iv) that the occurrence of deep desiccation is not merely dependent on the properties of the soil but is spatially heterogeneous. The study highlights the importance of soil moisture measurements for the understanding of moisture fluxes in the vadose zone.

scholarly journals Long-Term and High-Resolution Global Time Series of Brightness Temperature from Copula-Based Fusion of SMAP Enhanced and SMOS Data

2018 ◽  
Vol 10 (11) ◽  
pp. 1842 ◽  
Author(s):  
Christof Lorenz ◽  
Carsten Montzka ◽  
Thomas Jagdhuber ◽  
Patrick Laux ◽  
Harald Kunstmann
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
High Resolution ◽  
Brightness Temperature ◽  
Spatial Resolution ◽  
Prediction Models ◽  
Weather Prediction ◽  
Brightness Temperatures ◽  
Climate Analysis

Long and consistent soil moisture time series at adequate spatial resolution are key to foster the application of soil moisture observations and remotely-sensed products in climate and numerical weather prediction models. The two L-band soil moisture satellite missions SMAP (Soil Moisture Active Passive) and SMOS (Soil Moisture and Ocean Salinity) are able to provide soil moisture estimates on global scales and in kilometer accuracy. However, the SMOS data record has an appropriate length of 7.5 years since late 2009, but with a coarse resolution of ∼25 km only. In contrast, a spatially-enhanced SMAP product is available at a higher resolution of 9 km, but for a shorter time period (since March 2015 only). Being the fundamental observable from passive microwave sensors, reliable brightness temperatures (Tbs) are a mandatory precondition for satellite-based soil moisture products. We therefore develop, evaluate and apply a copula-based data fusion approach for combining SMAP Enhanced (SMAP_E) and SMOS brightness Temperature (Tb) data. The approach exploits both linear and non-linear dependencies between the two satellite-based Tb products and allows one to generate conditional SMAP_E-like random samples during the pre-SMAP period. Our resulting global Copula-combined SMOS-SMAP_E (CoSMOP) Tbs are statistically consistent with SMAP_E brightness temperatures, have a spatial resolution of 9 km and cover the period from 2010 to 2018. A comparison with Service Soil Climate Analysis Network (SCAN)-sites over the Contiguous United States (CONUS) domain shows that the approach successfully reduces the average RMSE of the original SMOS data by 15%. At certain locations, improvements of 40% and more can be observed. Moreover, the median NSE can be enhanced from zero to almost 0.5. Hence, CoSMOP, which will be made freely available to the public, provides a first step towards a global, long-term, high-resolution and multi-sensor brightness temperature product, and thereby, also soil moisture.

scholarly journals Response of Young and Maturing Citrus Trees Grown on a Sandy Soil to Irrigation Scheduling, Nitrogen Fertilizer Rate, and Nitrogen Application Method

HortScience ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 145-150 ◽  
Author(s):  
Kelly T. Morgan ◽  
T. Adair Wheaton ◽  
William S. Castle ◽  
Laurence R. Parsons
Keyword(s):  
Soil Moisture ◽  
Tree Growth ◽  
Irrigation Scheduling ◽  
Tree Age ◽  
N Application ◽  
Application Method ◽  
Canopy Volume ◽  
N Rates ◽  
Citrus Trees

This study examined the effect of irrigation rates, nitrogen (N) fertilizer rates, and methods of applying N on growth and productivity of young (3 to 5 years old) and maturing (8 to 10 years old) citrus trees. A long-term study was conducted with the following objectives: 1) to measure the main effects of N rate, N application method, and irrigation on citrus tree growth and production from planting to maturity; 2) to establish growth and production relationships for long-term N rates and irrigation on well-drained sandy Entisols; and 3) to determine the effect of split fertilizer applications at two soil moisture regimes on citrus growth and production for two tree age classes as trees mature. Irrigation was applied using two selected ranges of soil moisture tensions and annual N rate varied by tree age as percentages of recommended. Methods of applying N included a dry granular fertilizer (DGF) containing soluble N applied four times annually or a controlled-release fertilizer (CRF) applied once per year and fertigation applied either four (FG04) or 30 (FG30) times annually. Canopy size and yield were higher with the moderate irrigation rate compared with the low rate for both young and maturing trees. Critical N rates for both canopy volume and yield were between 178 and 200 kg·ha−1. The CRF and FG30 treatments produced larger trees and higher yields compared with FG04 and DGF in the young tree study, indicating that younger trees benefitted from frequent split fertilizer applications. As the trees matured and filled their allocated space, the two irrigation rates were continued and N was applied at six rates using either DGF or FG30. For these 8- to 10-year-old trees, critical values of N application rates were 210 and 204 kg·ha−1 for DGF and FG30, respectively. The absence of a significant interaction between N rate and application method indicated that N uptake efficiency was similar for all application methods tested. DGF and FG30 treatments resulted in similar maturing tree yields and fruit total soluble solids. Canopy volumes, for the same trees, were significantly greater all 3 years with the FG30 treatment compared with DGF. Thus, if increase in tree size is desired, increased number of split applications will likely promote tree growth; however, little increase in fruit yield may be obtained.

scholarly journals Modeling the long-term dynamics of tropical forests: from leaf traits to whole-tree growth patterns

2020 ◽  
Author(s):  
Gunnar Petter ◽  
Holger Kreft ◽  
Yongzhi Ong ◽  
Gerhard Zotz ◽  
Juliano Sarmento Cabral
Keyword(s):  
Tropical Forests ◽  
Functional Traits ◽  
Tree Growth ◽  
Tree Species ◽  
Leaf Traits ◽  
Forest Stand ◽  
Growth Patterns ◽  
Leaf Economic Spectrum ◽  
Individual Trees

AbstractTropical forests are the most diverse terrestrial ecosystems and home to numerous tree species with diverse ecological strategies competing for resources in space and time. Functional traits influence the ecophysiological performance of tree species, yet the relationship between traits and emergent long-term growth pattern is poorly understood. Here, we present a novel 3D forest stand model in which growth patterns of individual trees and forest stands are emergent properties of leaf traits. Individual trees are simulated as 3D functional-structural tree models (FSTMs), considering branches up to the second order and leaf dynamics at a resolution of one m3. Each species is characterized by a set of leaf traits that corresponds to a specific position on the leaf economic spectrum and determines light-driven carbon assimilation, respiration and mortality rates. Applying principles of the pipe model theory, these leaf scale-processes are coupled with within-tree carbon allocation, i.e., 3D tree growth emerges from low-level processes. By integrating these FSTMs into a dynamic forest stand model, we go beyond modern stand models to integrate structurally-detailed internal physiological processes with interspecific competition, and interactions with the environment in diverse tree communities. For model calibration and validation, we simultaneously compared a large number of emergent patterns at both the tree and forest levels in a pattern-oriented modeling framework. At the tree level, varying specific leaf area and correlated leaf traits determined the maximum height and age of a tree, as well as its size-dependent growth rate and shade tolerance. Trait variations along the leaf economic spectrum led to a continuous transition from fast-growing, short-lived and shade-intolerant to slow-growing, long-lived and shade-tolerant trees. These emerging patterns resembled well-known functional tree types, indicating a fundamental impact of leaf traits on long-term growth patterns. At the forest level, a large number of patterns taken from lowland Neotropical forests were reproduced, indicating that our forest model simulates structurally realistic forests over long time spans. Our ecophysiological approach improves the understanding of how leaf level processes scale up to the tree and the stand level, and facilitates the development of next-generation forest models for species-rich forests in which tree performance emerges directly from functional traits.

scholarly journals Tropical tree growth sensitivity to climate is driven by species intrinsic growth rate and leaf traits

2021 ◽  
Author(s):  
David Bauman ◽  
Claire Fortunel ◽  
Lucas A. Cernusak ◽  
Lisa P. Bentley ◽  
Sean M. McMahon ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Tree Species ◽  
Forest Dynamics ◽  
Species Traits ◽  
Growth Responses ◽  
Growth Data ◽  
Short Term ◽  
Evaporative Demand

A better understanding of how climate affects growth in tree species is essential for improved predictions of forest dynamics under climate change. Long-term climate averages (mean climate) and short-term deviations from these averages (anomalies) both influence tree growth, but the rarity of long-term data integrating climatic gradients with tree censuses has so far limited our understanding of their respective role, especially in tropical systems. Here, we combined 49 years of growth data for 509 tree species across 23 tropical rainforest plots along a climatic gradient to examine how tree growth responds to both climate means and anomalies, and how species functional traits mediate these tree growth responses to climate. We showed that short-term, anomalous increases in atmospheric evaporative demand and solar radiation consistently reduced tree growth. Drier forests and fast-growing species were more sensitive to water stress anomalies. In addition, species traits related to water use and photosynthesis partly explained differences in growth sensitivity to both long-term and short-term climate variations. Our study demonstrates that both climate means and anomalies shape tree growth in tropical forests, and that species traits can be leveraged to understand these demographic responses to climate change, offering a promising way forward to forecast tropical forest dynamics under different climate trajectories.

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