Spherical
Densiometer
Total light incident on the stream and the
resulting heat load are important factors regulating
biological activity in the stream.
The water column is the medium of support and
movement for fish and other aquatic organisms and is
strongly controlled by its bordering riparian
vegetation. The amount of sunlight, which is the
energy base for photosynthesis and stream
temperature, is also controlled by the surrounding
vegetation.
The concave Spherical Densiometer, Model B can be
used on permanent points or transects to estimate
relative vegetative canopy closure or canopy density
caused by vegetation. Vegetative canopy closure is
the area of the sky over the selected site (stream
channel) bracketed by vegetation.
The concave mirror surface of the Densiometer has
37 grid intersections forming 24 squares. At a
probability level of 95 percent, tests show that
average measurements of the same overstory area can
be expected to be within ±2.4 percent of the mean.
To take readings, hold the instrument level, 12"
to 18" in front of body and at elbow height. Assume
four equi-spaced dots to each square of the grid and
systematically count the dots equivalent to
quarter-square openings. Multiply the total count by
1.04 to obtain percent of overhead area not occupied
by canopy. The difference between this and 100 is an
estimation of overstory density in percent. Units
are housed in a 3" x 3" x 1" thick walnut case with
operating instructions permanently affixed to the
lid. A leveling bubble is also included for accurate
positioning during estimations.
Two models are available: Convex and Concave. The
readings from the Convex Densiometer are
representing a larger sample size area than those of
the concave unit.
607-089 Convex Densiometer 1 lb.
607-090 Concave Densiometer 1 lb.
Foot Candle/Lux
Meter
The Foot Candle/Lux Meter accurately measures the
light density under tree canopies over streams. It
measures light levels in terms of Foot Candles (Fc)
or Lux over a wide range and measures from 0 to 5000
Fc in three ranges: 0-200, 0-2000, 0-5000, with 0.1
Fc resolution. It will also measure 0-50,000 Lux in
three ranges: 0-2,000, 0-20,000, and 0-50,000, with
1 Lux resolution.
Meter comes equipped with a 1mV per count analog
output for downloading to a recorder. Includes one
9-volt battery. Dimensions: 6.4" x 2.89" x 1.2".
607-096 Foot Candle/Lux Meter 1 lb.
607-097 Vinyl Carrying Pouch 0.5 lb.
GRP
Densitometer
The GRP Densitometer offers a simple solution for
estimating canopy coverage. The 45 degree mirror
provides a quick and simple view of the immediate
canopy coverage. The internal levels allow getting
perfect 90 degree views with every reading.
Estimating your canopy coverage is very simple. For
example, if you take 100 equidistant readings along
a transverse and 56 of those readings show canopy
coverage, then your canopy coverage is 56%.
607-103 GRP Densitometer 0.8 lb.
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