Name:
Walter Charles Shortle
Country:
USA
City:
Milton Mills
State/Province:
NH
ACS Member:
Member
Local Section:
L109,Northeastern
International Chapter:
Technical Division Membership:
D511,Environmental Chemistry Division;D530,Geochemistry Division
Technical Division Membership Emeritus:
Subdivision Member:
ACS Activities:
Company/Institution Name:
Career Stage:
Professional
Research and Special Interests:
Over the past few decades, techniques of geospatial landscape mapping have made great progress, but geotemporal "mapping" remains a problem at decadal time scales. During the 20th Century rapidly changing forest-atmosphere interactions have altered the way forest trees are responding to changing climate factors, diseases and insects, and other disturbances. Information about the long-term impact of environmental change on forest ecosystems is recorded in the growth patterns and chemistry of tree rings. Interpreting the tree-ring record of radial growth requires an understanding of the effects of forest stand dynamics and internal influences of stem geometry and tree senescence. Interpreting the chemical record in tree rings requires separation of internal biochemical factors from external biogeochemical factors. Inferences about forest history gained from the study of dendroecology and dendrochemistry are critical to determine if spatial differences being mapped represent declining or recovering ecosystem health and productivity from which ecosystem services are derived.
The purpose of our ongoing work is to develop concepts and methods using precisely dated tree rings that link environmental changes of the past century to ecosystem response in the current century. Initial findings on the effect of Ca depletion, Al mobilization, and N saturation on the status of southern boreal forests of northwestern Russia and the Appalachian Mountains of the eastern U.S. following several decades of acid deposition have been presented. This work is being further developed and includes comparisons and contrasts with ecotonal northern temperate forests. Work to date indicates a broad variation in biological response to a changing environment among tree species and soil types.
The role of wood-decay fungi in the recovery of Ca depleted forest ecosystems is also being considered as a natural means to reestablish the biogeochemical cycle damaged by acid deposition and stabilize forests now being exposed to a changing climate. Forests with fully functioning biogeochemical cycles are needed to provide ecosystem goods and services. Better spatial maps without temporal dimensions will not provide key information about the direction, rate, and magnitude of the effects of environmental change. Better understanding of the relation of tree ring data to the forest environment can help establish the temporal dimension.
Area of Expertise:
tree biology, tree and wood diseases, biochemical protective systems in trees, electrical diagnostic methods, acidic deposition, dendrochemistry, and forest biogeochemistry
Years of Expertise:
26 or more