Distances between Stations

1
Evergreen Canopy Influence on Precipitation
Temperature, Syracuse Fall 2001 Art Graf, Kathy
Kelly, Pat Scanlon, and Dr. Ted Endreny FOR 338
Meteorology Course, 207 Marshall Hall, SUNY
College of Environmental Science and Forestry,
Syracuse, NY 13210
Introduction Does the presence of a Forest
Canopy have a significant impact on precipitation
(PPT) and air temperature? Objective to
determine Precipitation and Temperature
differences on an open canopy site as compared to
a canopy covered site. Hypotheses Ho null
hypothesis Ho Forest Canopy has no significant
impact on PPT and Air Temperature H1 Forest
Canopy has a significant impact on PPT and Air
Temperature
Map, Figures Results Map 1. This map shows the
location of stations and distances between
stations, where the trees are indicated in green.
Discussion The amount of throughfall
(precipitation reaching the forest floor or
gauge) is influenced by the presence of a canopy.
A vegetative surface such as tree canopies help
to protect the soil and reduce erosion. The
canopy also performs the function of intercepting
and redistributing precipitation and can alter
the chemical composition of this redistributed
rainfall. (Parker, 1995) Temperature influences
different processes within a forest. It plays an
important part in the energy balance of an
ecosystem. Studies have shown that average air
temperature differences were twice as large in
open canopy areas as they were in forested areas.
Large openings with open canopy exhibit more
extreme temperature, higher soil temperature and
increased wind speeds when compared with forest
interiors. Microclimate, which includes solar
radiation, moisture and temperature, is a primary
driver of ecosystem processes such as
photosynthesis, regeneration and plant growth.
Distances between Stations Trees 1
- 5 76 Ft. 2 4 Ft 2 in. from
tree 3 27 in. from tree 4 1 Ft.
from tree 5 - 4 32 in. 1 N
5 4 3 2
Old Greenhouse
Trees must exchange water, carbon dioxide and
energy with the atmosphere to survive. Because
they are efficient sources of water vapor and can
be significant sinks of carbon, forest canopies
are an important component of surface control on
climate from the local to global scales
(Fitzjarrald, 1995).
Forest canopies perform surface climatic control
by affecting both temperature and precipitation.
Fluctuations of temperature and humidity at
different levels in the canopy promote species
diversity within a forested ecosystem. There is
increasing attention being paid to the benefits
of the presence of trees in urban environments
for both ecosystems in general and humans.
Conclusions The
presence of a forest canopy does have an impact
on PPT and temperature. The vegetation in the
form of forest canopy cover plays an important
part in intercepting and redirecting PPT and in
temperature regulation. The significance of PPT
and temperature lies not in their individual
characteristics and patterns, but rather in how
they affect the myriad of other processes within
a forested or non-forested ecosystem. Our work
showed that vegetation in the form of a forest
canopy plays an important part in intercepting
PPT and regulating temperature on the Old
Greenhouse site.
1 2 4 3 5
Methods and Materials The experimental site was
located next to the old greenhouse south of Bray
Hall on the SUNY ESF campus, Syracuse, NY. PPT
was measured on a daily basis from 9/24 -
11/12/01 at 2 stations (12) and from 10/06
11/12/01 at 3 additional stations (3,45) A team
of 3 people monitored the gauges and recorded the
data. A total of five rain gauges were used.
Station 1 is located in the open with open canopy
and measures gross rainfall. Stations 2 through 5
are at various locations beneath the canopy of
two Thuja occidentalis (Northern White Cedar)
trees and measure throughfall. Stemflow was not
measured in this experiment.
Figure 1. A comparison of PPT totals for all
stations (10/16-11/09/01) shows larger amounts of
PPT recorded in the gauge at the open canopy
station with decreasing amounts recorded under
increasing canopy.
References 1. Parker, Geoffrey G. 1995 Structure
and Microclimate of Forest Canopies. Forest
Canopies eds. Lowman, Margaret A., and Nalini M.
Nadkarni San Diego, Ca. Academic Press Inc.
73-106 2. Fitzjarrald, David R. Moore Kathleen
E. 1995. Physical Mechanisms of Heat and Mass
Exchange between Forests and Atmosphere. Forest
Canopies eds. Lowman, Margaret A., and Nalini M.
Nadkarni San Diego, Ca. Academic Press Inc. 45-69
PPT data was collected using five non-recording
Taylor rain gauges which measure 2 x 12 and
were placed approximately 5 feet above the
ground. These are simple cylinders, which catch
the rainfall, are read manually and must be
emptied at regular intervals. The minimum
detection ability of these gauges is .01
inches. Temperature was measured using two ErTco
Max/Min thermometers calibrated for both
Fahrenheit and Celsius readings. The thermometers
were located at stations 1 2.Temperature data
were recorded in the Celsius scale.
Figure 2. This graph compares Max and Min
Temperature at No Canopy Canopy stations. The
greater amplitudes between maximum and minimum
temperature in the canopied and open canopied
sites.