[MCN] pdf: Forest Service update on drought and forests of the US

[Lance Olsen]

Echohydrological implications of drought for forests in the United States
Vose, James M.; Miniat, Chelcy Ford; Luce, 
Charles H.; Asbjornsen, Heidi; Caldwell, Peter 
V.; Campbell, John L.; Grant, Gordon E.; Isaak, 
Daniel J.; Loheide, Steven P.; Sun, Ge. 2016.

Date: 2016
Source: Forest Ecology and Management (IN PRESS)
Station ID: JRNL-SRS-2016

PDF
http://www.srs.fs.usda.gov/pubs/ja/2016/ja_2016_vose_001.pdf

Abstract: The relationships among drought, 
surface water flow, and groundwater recharge are 
not straightforward for most forest ecosystems 
due to the strong role that vegetation plays in 
the forest water balance. Hydrologic responses to 
drought can be either mitigated or exacerbated by 
forest vegetation depending upon vegetation water 
use and how forest population dynamics respond to 
drought. Understanding how drought impacts 
ecosystems requires understanding how drought 
impacts ecohydrological processes. Because 
different species and functional groups vary in 
their ecophysiological traits that influence 
water use patterns, changes in species 
assemblages can alter hydrological processes from 
the stand to the watershed scales. Recent warming 
trends and more prolonged and frequent droughts 
have accelerated the spread and intensity of 
insect attacks in the western US that kill nearly 
all of the canopy trees within forest stands, 
changing the energy balance of the land surface 
and affecting many hydrologic processes. In 
contrast, some eastern forest tree species and 
size classes can tolerate drought better than 
others, suggesting the potential for 
drought-mediated shifts in both species 
composition and structure. Predicting how these 
changes will impact hydrologic processes at 
larger spatial and temporal scales presents a 
considerable challenge. The biogeochemical 
consequences of drought, such as changes in 
stream chemistry, are closely linked to 
vegetation dynamics and hydrologic responses. As 
with other natural disturbances, droughts are 
difficult to prepare for because they are 
unpredictable. However, there are management 
options that may be implemented to minimize the 
impacts of drought on water quantity and quality. 
Examples include reducing leaf area by thinning 
and regenerating cut forests with species that 
consume less water, although a high level of 
uncertainty in both drought projections and 
anticipated responses suggests the need for 
monitoring and adaptive management.
                 Citation: Vose, James M.; Miniat, 
Chelcy Ford; Luce, Charles H.; Asbjornsen, Heidi; 
Caldwell, Peter V.; Campbell, John L.; Grant, 
Gordon E.; Isaak, Daniel J.; Loheide, Steven P.; 
Sun, Ge. 2016. Echohydrological implications of 
drought for forests in the United States.
-- 
================================== Net Primary 
Production ==============================

"Only about a tenth of 1 percent of the energy 
received from the sun by the earth is fixed by 
photosynthesis ...."

"Worldwide it is about the equivalent to the 
annual production of between 150 and 200 billion 
tons of dry organic matter and includes both food 
for man and the energy that runs the life support 
systems of the biosphere ... "

"It is solar energy that moves the rabbit, the 
deer, the whale, the boy on the bicycle outside 
my window, my pencil as I write these wordsŠ 
Expanding human activities are requiring a larger 
fraction of the total and are paradoxically 
making large segments of it less useful in 
support of man."

Woodwell, George.
"The Energy Cycle of the Biosphere."
Scientific American. September, 1970
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