Relationships between individual‐tree mortality and water‐balance variables indicate positive trends in water stress‐induced tree mortality across North America

2016 ◽  
Vol 23 (4) ◽  
pp. 1691-1710 ◽  
Author(s):  
Robbie A. Hember ◽  
Werner A. Kurz ◽  
Nicholas C. Coops
Keyword(s):  
Water Stress ◽  
North America ◽  
Water Balance ◽  
Tree Mortality ◽  
Individual Tree

scholarly journals SurEau: a mechanistic model of plant water relations under extreme drought

2021 ◽  
Vol 78 (2) ◽  
Author(s):  
Hervé Cochard ◽  
François Pimont ◽  
Julien Ruffault ◽  
Nicolas Martin-StPaul
Keyword(s):  
Water Stress ◽  
Water Balance ◽  
Water Relations ◽  
Tree Mortality ◽  
Mechanistic Model ◽  
Climatic Conditions ◽  
Extreme Drought ◽  
Volume Curve ◽  
Oak Trees ◽  
Pressure Volume Curve

Abstract Key message A new process-based model,SurEau, is described. It predicts the risk of xylem hydraulic failure under drought. Context The increase in drought intensity due to climate change will accentuate the risk of tree mortality. But very few process-based models are currently able to predict this mortality risk. Aims We describe the operating principle of a new mechanistic model SurEau that computes the water balance, water relations, and hydraulics of a plant under extreme drought. Methods SurEau is based on the formalization of key physiological processes of plant response to water stress. The hydraulic and hydric functioning of the plant is at the core of this model, which focuses on both water flows (i.e., hydraulic) and water pools (i.e., hydric) using variable hydraulic conductances. The model considers the elementary flow of water from the soil to the atmosphere through different plant organs that are described by their symplasmic and apoplasmic compartments. For each organ, the symplasm is described by a pressure-volume curve and the apoplasm by its vulnerability curve to cavitation. The model is evaluated on mature oak trees exposed to water stress. Results On the tested oak trees, the model captures well the observed soil water balance, water relations, and level of embolism. A sensitivity analysis reveals that the level of embolism is strongly determined by air VPD and key physiological traits such as cuticular transpiration, resistance to cavitation, and leaf area. Conclusion The process-based SurEau model offers new opportunities to evaluate how different species or genotypes will respond to future climatic conditions.

scholarly journals Managing bark beetle outbreaks (Ips typographus, Dendroctonus spp.) in conservation areas in the 21st century

2016 ◽  
Vol 77 (4) ◽  
pp. 352-357
Author(s):  
Dominik Kulakowski
Keyword(s):  
North America ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Tree Mortality ◽  
Forest Health ◽  
Scientific Data ◽  
Timber Production ◽  
Conservation Areas ◽  
Silvicultural Treatments ◽  
Social Scientific

Abstract Forests in Europe and North America are being affected by large and severe outbreaks of bark beetles, which have caused widespread concern about forest health and have led to proposals for tree removal in affected or susceptible forests. Any such intervention, as well as broader decisions of whether any active interventions are appropriate, should be based on the best scientific data. This is true for all forests, including those whose purposes include timber production, watershed protection, biogeochemical function and recreation, and especially protected and conservation areas as the latter often provide particularly unique and important cultural, social, scientific and other ecosystem services. Here, I summarize peer-reviewed literature on the effects of bark beetle outbreaks and on silvicultural treatments aimed at mitigating beetle-induced tree mortality. From an objective scientific perspective, beetle outbreaks do not destroy forests. Instead, in many cases they play an important role in promoting wildlife, biodiversity and other ecological services. The best available data indicate that logging in conservation areas is unlikely to stop ongoing bark beetle outbreaks and instead may be more ecologically detrimental to the forests than the outbreaks themselves. If the purpose of a forest is timber production, then logging is desirable and can be planned based on appropriate analyses of timber yield and economic profit. However, in areas in which conservation is the determined goal, it is recommended that cutting trees be limited to removing hazards, such as trees that might fall in areas of high human activity in order to limit property damage and personal injury. Based on extensive research in Europe and North America, logging beetle-affected forests is inconsistent with most conservation goals.

Modeling individual tree mortality for white spruce in Alberta

2003 ◽  
Vol 163 (3) ◽  
pp. 209-222 ◽  
Author(s):  
Yuqing Yang ◽  
Stephen J Titus ◽  
Shongming Huang
Keyword(s):  
Tree Mortality ◽  
White Spruce ◽  
Individual Tree

Detecting early warning signals of tree mortality in boreal North America using multiscale satellite data

2018 ◽  
Vol 24 (6) ◽  
pp. 2284-2304 ◽  
Author(s):  
Brendan M. Rogers ◽  
Kylen Solvik ◽  
Edward H. Hogg ◽  
Junchang Ju ◽  
Jeffrey G. Masek ◽  
...  
Keyword(s):  
North America ◽  
Satellite Data ◽  
Early Warning ◽  
Tree Mortality ◽  
Warning Signals ◽  
Early Warning Signals

Detection of Adelges tsugae (Hemiptera: Adelgidae) wool using Velcro-covered balls

2021 ◽  
pp. 1-11
Author(s):  
Jeffrey G. Fidgen ◽  
Mark C. Whitmore ◽  
Chris J.K. MacQuarrie ◽  
Jean J. Turgeon
Keyword(s):  
Life Cycle ◽  
North America ◽  
Insect Pest ◽  
Adelges Tsugae ◽  
Eastern North America ◽  
Sample Sizes ◽  
Field Sampling ◽  
Individual Tree ◽  
Precision Level ◽  
The Relationship

Abstract Adelges tsugae Annand (Hemiptera: Adelgidae), a nonindigenous insect pest of hemlock (Tsuga spp.) (Pinaceae) in eastern North America, spends most of its life cycle within an ovisac, which resembles a woolly white mass on twigs. We evaluated the probability of detecting adelgid wool with Velcro®-covered balls when taking an increasing number of samples per tree (field sampling) and number of trees per simulated stand. We examined the relationship between the detection of adelgid wool using this technique and the incidence of A. tsugae-infested twigs by sampling lower-crown branch tips of the same trees. We found that the probability of detecting wool with ball sampling increased with number of ball samples per tree, with number of trees per simulated stand, and with increasing incidence of ovisacs in the lower crown. When sampling an individual tree, we found that 20 ball samples per tree achieved a targeted precision level of 0.75, but when sampling a stand, we found that 10 ball samples per tree took the least time for the range of simulated A. tsugae infestations we tested. These sample sizes are recommended for detection of A. tsugae infestations on an individual tree and in a hemlock stand.

scholarly journals A conceptual dynamic vegetation-soil model for arid and semiarid zones

2008 ◽  
Vol 12 (5) ◽  
pp. 1175-1187 ◽  
Author(s):  
D. I. Quevedo ◽  
F. Francés
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Water Balance ◽  
Water Availability ◽  
Leaf Biomass ◽  
Soil Conditions ◽  
Model Parameters ◽  
Arid Zones ◽  
Soil Model ◽  
Arid And Semiarid

Abstract. Plant ecosystems in arid and semiarid climates show high complexity, since they depend on water availability to carry out their vital processes. In these climates, water stress is the main factor controlling vegetation development and its dynamic evolution. The available water-soil content results from the water balance in the system, where the key issues are the soil, the vegetation and the atmosphere. However, it is the vegetation, which modulates, to a great extent, the water fluxes and the feedback mechanisms between soil and atmosphere. Thus, soil moisture content is most relevant for plant growth maintenance and final water balance assessment. A conceptual dynamic vegetation-soil model (called HORAS) for arid and semi-arid zones has been developed. This conceptual model, based on a series of connected tanks, represents in a way suitable for a Mediterranean climate, the vegetation response to soil moisture fluctuations and the actual leaf biomass influence on soil water availability and evapotranspiration. Two tanks were considered using at each of them the water balance and the appropriate dynamic equation for all considered fluxes. The first one corresponds to the interception process, whereas the second one models the evolution of moisture by the upper soil. The model parameters were based on soil and vegetation properties, but reduced their numbers. Simulations for dominant species, Quercus coccifera L., were carried out to calibrate and validate the model. Our results show that HORAS succeeded in representing the vegetation dynamics and, on the one hand, reflects how following a fire this monoculture stabilizes after 9 years. On the other hand, the model shows the adaptation of the vegetation to the variability of climatic and soil conditions, demonstrating that in the presence or shortage of water, the vegetation regulates its leaf biomass as well as its rate of transpiration in an attempt to minimize total water stress.

Sign in / Sign up

Export Citation Format

Share Document