Spruce beetle outbreak was not driven by drought stress: Evidence from a tree‐ring iso‐demographic approach indicates temperatures were more important

Jessika M. Pettit; Steve L. Voelker; R. Justin DeRose; Julia I. Burton

doi:10.1111/gcb.15274

Spruce beetle outbreak was not driven by drought stress: evidence from a tree-ring iso-demographic approach indicate temperatures were more important

Authorea ◽

10.22541/au.158523071.17715360 ◽

2020 ◽

Author(s):

Jessika Pettit ◽

Steve Voelker ◽

R Justin DeRose ◽

Julia Burton

Keyword(s):

Drought Stress ◽

Tree Ring ◽

Spruce Beetle ◽

Demographic Approach

The emergent past: past natural and human disturbances of trees can reduce their present resistance to drought stress

European Journal of Forest Research ◽

10.1007/s10342-021-01422-8 ◽

2021 ◽

Author(s):

Hans Pretzsch

Keyword(s):

Drought Stress ◽

Memory Effect ◽

Tree Ring ◽

Tree Growth ◽

Water Retention ◽

Annual Growth ◽

Recent Past ◽

Ecological Memory ◽

Growth Variation

AbstractForest tree growth is primarily explained, modelled, and predicted depending on current age or size, environmental conditions, and competitive status in the stand. The accumulated size is commonly used as a proxy for a tree's past development. However, recent studies suggest that antecedent conditions may impact present growth by epigenetic, transcriptional, proteomic, or metabolic changes alongside physiological and structural properties. Here, I analysed the ecological memory effect embedded in the xylem as a tree-ring structure. I used 35 mature Norway spruces (Picea abies (L.) H. Karst.) and 36 European beeches (Fagus sylvatica L.) of the Kranzberg Forest water retention experiment KROOF in South Germany to scrutinise how their past development determines the growth of control plots and plots with 5-year water retention. I hypothesised that the current size and growing conditions determine tree growth and drought stress resistance. Metrics quantifying the trees’ recent and past growth, and correlation and linear mixed models with random effects revealed the following ecological memory effects. (1) For both species, the progressive growth course, low inter-annual growth variation in the long term, and low growth deflections in the recent past increased the growth resistance to drought. (2) The correlation between the past growth metrics and current stress reactions revealed that legacy effects could reach back 5–30 years; I found short- and long-term ecological memory. (3) Parameters of model prediction of the basic model with only size as a predictor of tree growth could be improved. The results suggest differences in the internal stem structure and ring pattern cause-specific differences in the trees' functioning and growth. I conclude that a long-term progressive increase and low variation in ring width may improve water conduction and reduce embolism in both species. Annual growth variation and low growth events in the recent past may have primed the morphology and allocation of the Norway spruce to better resist drought. The strong reduction in current growth, drought resistance by irregular growth, and past growth disturbances reveal a memory effect embedded in the tree ring pattern, suggesting further exploration and consideration in tree monitoring, growth modelling, and silvicultural prescriptions.

Modeling regional drought-stress indices for beech forests in Mediterranean mountains based on tree-ring data

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2018.11.015 ◽

2019 ◽

Vol 265 ◽

pp. 110-120 ◽

Cited By ~ 7

Author(s):

Roberto Tognetti ◽

Bruno Lasserre ◽

Mirko Di Febbraro ◽

Marco Marchetti

Keyword(s):

Drought Stress ◽

Tree Ring ◽

Beech Forests ◽

Stress Indices ◽

Tree Ring Data ◽

Mediterranean Mountains ◽

Regional Drought

The resistance and resilience of European beech seedlings to drought stress during the period of leaf development

Tree Physiology ◽

10.1093/treephys/tpaa066 ◽

2020 ◽

Vol 40 (9) ◽

pp. 1147-1164

Author(s):

Roman Gebauer ◽

Roman Plichta ◽

Josef Urban ◽

Daniel Volařík ◽

Martina Hájíčková

Keyword(s):

Drought Stress ◽

Hydraulic Conductivity ◽

Gas Exchange ◽

Tree Ring ◽

Leaf Development ◽

Leaf Gas Exchange ◽

Recovery Period ◽

European Beech ◽

Leaf Biomass ◽

Severe Drought

Abstract Spring drought is becoming a frequently occurring stress factor in temperate forests. However, the understanding of tree resistance and resilience to the spring drought remains insufficient. In this study, European beech (Fagus sylvatica L.) seedlings at the early stage of leaf development were moderately and severely drought stressed for 1 month and then subjected to a 2-week recovery period after rewatering. The study aimed to disentangle the complex relationships between leaf gas exchange, vascular anatomy, tree morphology and patterns of biomass allocation. Stomatal conductance decreased by 80 and 85% upon moderate and severe drought stress, respectively, which brought about a decline in net photosynthesis. However, drought did not affect the indices of slow chlorophyll fluorescence, indicating no permanent damage to the light part of the photosynthetic apparatus. Stem hydraulic conductivity decreased by more than 92% at both drought levels. Consequently, the cambial activity of stressed seedlings declined, which led to lower stem biomass, reduced tree ring width and a lower number of vessels in the current tree ring, these latter also with smaller dimensions. In contrast, the petiole structure was not affected, but at the cost of reduced leaf biomass. Root biomass was reduced only by severe drought. After rewatering, the recovery of gas exchange and regrowth of the current tree ring were observed, all delayed by several days and by lower magnitudes in severely stressed seedlings. The reduced stem hydraulic conductivity inhibited the recovery of gas exchange, but xylem function started to recover by regrowth and refilling of embolized vessels. Despite the damage to conductive xylem, no mortality occurred. These results suggest the low resistance but high resilience of European beech to spring drought. Nevertheless, beech resilience could be weakened if the period between drought events is short, as the recovery of severely stressed seedlings took longer than 14 days.

Dendroecological detection of spruce bark beetle outbreaks in northwestern Colorado

Canadian Journal of Forest Research ◽

10.1139/x00-104 ◽

2000 ◽

Vol 30 (11) ◽

pp. 1788-1798 ◽

Cited By ~ 33

Author(s):

Karen S Eisenhart ◽

Thomas T Veblen

Keyword(s):

Tree Ring ◽

Bark Beetle ◽

Large Scale ◽

Tree Mortality ◽

Subalpine Forests ◽

Spruce Bark Beetle ◽

Engelmann Spruce ◽

Spruce Bark ◽

Photographic Evidence ◽

Spruce Beetle

Episodic outbreaks of Dendroctonus rufipennis (Kirby), the spruce bark beetle, have greatly influenced the structure of subalpine forests in northern Colorado. During the 1940s, much of the subalpine zone of northwestern Colorado was severely affected by beetle outbreak; also, tree-ring and photographic evidence suggest that large-scale outbreaks occurred in the 19th century. The present study focused on tree-ring methods to examine the regional extent and synchrony of pre-20th-century beetle outbreaks in northwestern Colorado. Results from examination of both live and dead Engelmann spruce (Picea engelmannii Parry ex Engelm.) tree rings in nine stands were compared with results of previous tree-ring studies in the same region. Evidence of past canopy disturbance included episodes of tree mortality in conjunction with sustained increases in radial growth rates. We identified regional outbreaks of spruce beetle by synchronous and sustained growth release in trees from disjunct stands. These new tree-ring records, along with previously published records, indicate that severe and widespread canopy disturbances, probably spruce beetle outbreaks, affected northwestern Colorado in 1716-1750, 1827-1845, 1860-1870, and 1940-1960. These results support earlier findings that large-scale outbreaks of spruce beetle have long been an important component of the dynamics of subalpine forests in Colorado.

Lack of genetic variation in tree ring 13C suggests a uniform, stomatally-driven response to drought stress across Pinus radiata genotypes

Tree Physiology ◽

10.1093/treephys/tpn015 ◽

2008 ◽

Vol 29 (2) ◽

pp. 191-198 ◽

Cited By ~ 8

Author(s):

D. M. Rowell ◽

P. K. Ades ◽

M. Tausz ◽

S. K. Arndt ◽

M. A. Adams

Keyword(s):

Genetic Variation ◽

Drought Stress ◽

Tree Ring ◽

Pinus Radiata

Dendrochronological Potential of Drought-Sensitive Tree Stands in Armenia for the Hydroclimate Reconstruction of the Lesser Caucasus

Atmosphere ◽

10.3390/atmos12020153 ◽

2021 ◽

Vol 12 (2) ◽

pp. 153

Author(s):

Magdalena Opała-Owczarek ◽

Hrachuhi Galstyan ◽

Piotr Owczarek ◽

Hovik Sayadyan ◽

Trahel Vardanyan

Keyword(s):

Drought Stress ◽

Tree Ring ◽

Climatic Variability ◽

Ring Width ◽

Summer Precipitation ◽

Negative Influence ◽

Positive Influence ◽

The Black Sea ◽

Local Climate ◽

Tree Ring Data

Existing high-resolution reconstructions of hydroclimate variability in the Caucasus are lacking tree-ring data from Armenian Plateau, the most continental part of the region. Our research presents the first dendrochronological investigation in Armenia. Juniper and oak tree-ring width chronologies were constructed, the longest spanning the last 140 years. The positive influence of spring–summer precipitation and the negative influence of temperature suggest drought stress at the investigated sites. Moving correlation analysis indicated a significant change over time in the sensitivity of investigated trees to climatic variability; juniper, previously sensitive to both temperature and precipitation, has shown especially strong precipitation signals in the recent decades since the local climate has turned more arid. Ongoing climate change increases drought stress in juniper, which may have further consequences on semiarid ecosystems. Our results reveal multiannual droughts recorded by tree rings, emerging in most parts of the Black Sea–Caspian Sea region.

Forest Drought Response Index (ForDRI): A New Combined Model to Monitor Forest Drought in the Eastern United States

Remote Sensing ◽

10.3390/rs12213605 ◽

2020 ◽

Vol 12 (21) ◽

pp. 3605

Author(s):

Tsegaye Tadesse ◽

David Y. Hollinger ◽

Yared A. Bayissa ◽

Mark Svoboda ◽

Brian Fuchs ◽

...

Keyword(s):

Drought Stress ◽

Tree Ring ◽

National Parks ◽

Forest Ecosystems ◽

Principal Component ◽

Bowen Ratio ◽

Hybrid Index ◽

Annual Increment ◽

Evaporative Demand ◽

Ratio Data

Monitoring drought impacts in forest ecosystems is a complex process because forest ecosystems are composed of different species with heterogeneous structural compositions. Even though forest drought status is a key control on the carbon cycle, very few indices exist to monitor and predict forest drought stress. The Forest Drought Indicator (ForDRI) is a new monitoring tool developed by the National Drought Mitigation Center (NDMC) to identify forest drought stress. ForDRI integrates 12 types of data, including satellite, climate, evaporative demand, ground water, and soil moisture, into a single hybrid index to estimate tree stress. The model uses Principal Component Analysis (PCA) to determine the contribution of each input variable based on its covariance in the historical records (2003–2017). A 15-year time series of 780 ForDRI maps at a weekly interval were produced. The ForDRI values at a 12.5km spatial resolution were compared with normalized weekly Bowen ratio data, a biophysically based indicator of stress, from nine AmeriFlux sites. There were strong and significant correlations between Bowen ratio data and ForDRI at sites that had experienced intense drought. In addition, tree ring annual increment data at eight sites in four eastern U.S. national parks were compared with ForDRI values at the corresponding sites. The correlation between ForDRI and tree ring increments at the selected eight sites during the summer season ranged between 0.46 and 0.75. Generally, the correlation between the ForDRI and normalized Bowen ratio or tree ring increment are reasonably good and indicate the usefulness of the ForDRI model for estimating drought stress and providing decision support on forest drought management.

Forest Drought Response Index (ForDRI): A New Combined Model to Monitor Forest Drought in the Eastern United States

10.20944/preprints202009.0673.v1 ◽

2020 ◽

Author(s):

Tsegaye Tadesse ◽

David Y. Hollinger ◽

Yared A. Bayissa ◽

Mark Svoboda ◽

Brian Fuchs ◽

...

Keyword(s):

Drought Stress ◽

Tree Ring ◽

National Parks ◽

Forest Ecosystems ◽

Principal Component ◽

Bowen Ratio ◽

Hybrid Index ◽

Annual Increment ◽

Evaporative Demand ◽

Ratio Data

Monitoring drought impacts in forest ecosystems is a complex process, because forest ecosystems are composed of different species with heterogeneous structural compositions. Even though forest drought status is a key control on the carbon cycle, very few indices exist to monitor and predict forest drought stress. The Forest Drought Indicator (ForDRI) is a new monitoring tool developed by the National Drought Mitigation Center (NDMC) to identify forest drought stress. ForDRI integrates 12 types of data, including satellite, climate, evaporative demand, ground water, and soil moisture, into a single hybrid index to estimate tree stress. The model uses Principal Component Analysis (PCA) to determine the contribution of each input variable based on its covariance in the historical records (2003–2017). A 15-year time series of 780 ForDRI maps at a weekly interval were produced. The ForDRI values at a 12.5km spatial resolution were compared with normalized weekly Bowen ratio data, a biophysically based indicator of stress, from nine AmeriFlux sites. There were strong and significant correlations between Bowen ratio data and ForDRI at sites that had experienced intense drought. In addition, tree ring annual increment data at eight sites in four eastern U.S. national parks were compared with ForDRI values at the corresponding sites. The correlation between ForDRI and tree ring increments at the selected eight sites during the summer season ranged between 0.46 and 0.75. Generally, the correlation between the ForDRI and normalized Bowen ratio or tree ring increment are reasonably good and indicate the usefulness of the ForDRI model for estimating drought stress and providing decision support on forest drought management.

Linking Increasing Drought Stress to Scots Pine Mortality and Bark Beetle Infestations

The Scientific World JOURNAL ◽

10.1100/tsw.2007.58 ◽

2007 ◽

Vol 7 ◽

pp. 231-239 ◽

Cited By ~ 60

Author(s):

Matthias Dobbertin ◽

Beat Wermelinger ◽

Christof Bigler ◽

Matthias Bürgi ◽

Mathias Carron ◽

...

Keyword(s):

Drought Stress ◽

Tree Ring ◽

Scots Pine ◽

Bark Beetle ◽

Drought Index ◽

Summer Drought ◽

Forest Protection ◽

Mortality Index ◽

Rhone Valley

In the dry Swiss Rhone Valley, Scots pine forests have experienced increased mortality in recent years. It has commonly been assumed that drought events and bark beetles fostered the decline, however, whether bark beetle outbreaks increased in recent years and whether they can be linked to drought stress or increasing temperature has never been studied.In our study, we correlated time series of drought indices from long-term climate stations, 11-year mortality trends from a long-term research plot, and mortality probabilities modeled from tree rings (as an indicator of tree vitality) with documented occurrences of various bark beetle species and a buprestid beetle, using regional Forest Service reports from 1902 to 2003 and advisory cases of the Swiss Forest Protection Service (SFPS) from 1984 to 2005. We compared the historical findings with measured beetle emergence from a 4-year tree felling and breeding chamber experiment.The documented beetle-related pine mortality cases increased dramatically in the 1990s, both in the forest reports and the advisory cases. The incidents of beetle-related pine mortality correlated positively with spring and summer temperature, and with the tree-ring-based mortality index, but not with the drought index. The number of advisory cases, on the other hand, correlated slightly with summer drought index and temperature, but very highly with tree-ringbased mortality index. The tree-ring-based mortality index and observed tree mortality increased in years following drought. This was confirmed by the beetle emergences from felled trees. Following dry summers, more than twice as many trees were colonized by beetles than following wet summers.We conclude that increased temperatures in the Swiss Rhone Valley have likely weakened Scots pines and favored phloeophagous beetle population growth. Beetles contributed to the increased pine mortality following summer drought. Among the factors not addressed in this study, changed forest use may have also contributed to increased beetle populations and Scots pine mortality, whereas air pollution seems to be of lesser importance.