Functionally relevant climate variables for arid lands: a climatic water deficit approach for modelling desert shrub distributions

2015 ◽  
Vol 42 (10) ◽  
pp. 1986-1997 ◽  
Author(s):  
Thomas E. Dilts ◽  
Peter J. Weisberg ◽  
Camie M. Dencker ◽  
Jeanne C. Chambers
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael J. Koontz ◽  
Andrew M. Latimer ◽  
Leif A. Mortenson ◽  
Christopher J. Fettig ◽  
Malcolm P. North

AbstractThe recent Californian hot drought (2012–2016) precipitated unprecedented ponderosa pine (Pinus ponderosa) mortality, largely attributable to the western pine beetle (Dendroctonus brevicomis; WPB). Broad-scale climate conditions can directly shape tree mortality patterns, but mortality rates respond non-linearly to climate when local-scale forest characteristics influence the behavior of tree-killing bark beetles (e.g., WPB). To test for these cross-scale interactions, we conduct aerial drone surveys at 32 sites along a gradient of climatic water deficit (CWD) spanning 350 km of latitude and 1000 m of elevation in WPB-impacted Sierra Nevada forests. We map, measure, and classify over 450,000 trees within 9 km2, validating measurements with coincident field plots. We find greater size, proportion, and density of ponderosa pine (the WPB host) increase host mortality rates, as does greater CWD. Critically, we find a CWD/host size interaction such that larger trees amplify host mortality rates in hot/dry sites. Management strategies for climate change adaptation should consider how bark beetle disturbances can depend on cross-scale interactions, which challenge our ability to predict and understand patterns of tree mortality.


2008 ◽  
Vol 97 (3-4) ◽  
pp. 219-233 ◽  
Author(s):  
Cr. Paltineanu ◽  
I. F. Mihailescu ◽  
Zoia Prefac ◽  
Carmen Dragota ◽  
Felicia Vasenciuc ◽  
...  

Author(s):  
Dumitru Mihăilă ◽  
Petruț-Ionel Bistricean ◽  
Liliana Gina Lazurca ◽  
Andrei-Emil Briciu

2017 ◽  
Vol 217 (1) ◽  
pp. 8-11 ◽  
Author(s):  
Alicia Ledo ◽  
Keryn I. Paul ◽  
David F. R. P. Burslem ◽  
John J. Ewel ◽  
Craig Barton ◽  
...  

1990 ◽  
Vol 20 (3) ◽  
pp. 357-364 ◽  
Author(s):  
E. O. Robertson ◽  
L. A. Jozsa ◽  
D. L. Spittlehouse

The relationships between annual tree-ring growth and growing season climate were explored, studying 70-year-old coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees in three sites of different moisture microclimates within productive forest lands. Climate data were augmented via a water balance model to calculate soil moisture deficits. Eleven ring variable components were derived via X-ray densitometry for each ring from two cores for each of 10 trees per site. First principal component scores of each ring variable were linked to climate variables (from 1951 to 1985) via multiple regression. Annual water deficit was found to account for 51% of the annual variations in ring weight. Earlywood width showed little direct climate response, and earlywood density was the least variable ring component. Latewood width was related to annual water deficit (r2 = 0.47). Latewood density showed different relationships to climate variables at the different sites. Percent latewood is increased by spring rainfall and depressed by high August temperatures. The ranges between minimum to maximum and earlywood to latewood densities were comparable for all sites, indicating that there is little density variation due to site differences.


2011 ◽  
Vol X (1) ◽  
pp. 140-148 ◽  
Author(s):  
Carmen-Sofia Dragotă ◽  
Monica Dumitraşcu ◽  
Ines Grigorescu ◽  
Gheorghe Kucsicsa

2012 ◽  
Vol 42 (4) ◽  
pp. 749-765 ◽  
Author(s):  
Constance I. Millar ◽  
Robert D. Westfall ◽  
Diane L. Delany ◽  
Matthew J. Bokach ◽  
Alan L. Flint ◽  
...  

Whitebark pine ( Pinus albicaulis Engelm.) in subalpine zones of eastern California experienced significant mortality from 2007 to 2010. Dying stands were dense (mean basal area 47.5 m2/ha), young (mean 176 years), and even-age; mean stand mortality was 70%. Stands were at low elevations (mean 2993 m), on northerly aspects, and experienced warmer, drier climates relative to the regional species distribution. White pine blister rust was not observed; mountain pine beetle infestations were extensive. Ring widths were negatively correlated with climatic water deficit and positively correlated with water-year precipitation. Although trees that survived had greater growth during the 20th century than trees that died, in the 19th century trees that eventually died grew better than trees that survived, suggesting selection for genetic adaptation to current climates as a result of differential tree mortality. Air surveys (2006–2010) in the Sierra Nevada, Mt. Shasta, and Warner Mountains showed similar trends to the intensive studies. Observed mortality from air surveys was highest in the Warner Mountains (38%) and lowest in the Sierra Nevada (5%); northern aspects at lower elevations within each mountain region had the highest probabilities of mortality and dying stands had higher climatic water deficit. Scenarios for the future of whitebark pine in California are discussed.


2012 ◽  
Vol 26 (2) ◽  
pp. 159-165 ◽  
Author(s):  
C. Paltineanu ◽  
E. Chitu ◽  
E. Mateescu

New trends for reference evapotranspiration and climatic water deficitThe paper deals with the trend for Penman-Monteith reference evapotranspiration and climatic water deficit during the first decade of the 21st century in Southern Romaniavsthe 20th century. For the first half of the year the monthly evapotranspiration values were higher for the first decade of the 21st centuryvsthe means of the 20th century. However, the trend reverses for the second half of the year, but for the whole year the totals were higher for the first decade of the 21st centuryvsthe totals of the 20th century. The yearly temperature means in the first decade of the XXI century showed an increase in the three locations studied, respectively,vscentury XX. This warming is responsible to a great extent for the increase in evapotranspiration, and the relationship between evapotranspiration and temperature was highly significant. Water deficit decreased in Constanta and Pitesti, but there was a slight increase in water deficit in the same period in Bucharest-Baneasa. Water deficit increased in the first half of the year and decreased in the second half during the first decade of century XXI in all the three locations investigatedvscentury XX.


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