Slope Correction.pdf

forest

1. Imagine a flat plane over the plot and extend the boundaries of the plot on the
ground
20m
18.79m
20
o
To calculate the radius of the plot in
the plane along the slope use the
following equation:
Radius
plane= Radius
field*cosine(slope)
= 20 * cosine(20
o
)
= 20*0.9397
= 18.794 m

2. You measured 50 trees in a circular plot of 1,000 m
2
. The plot was set up on a hill
with a slope of 30
o
. How would you scale your plot level data up to trees per
hectare?

3. How many trees in one hectare if there are 50 trees in a
circular plot of 1,000 m
2
on a slope of 30
O
?
1.Without slope correction:
EpF= 10,000/1,000 = 10 => 50*10 = 500 trees per ha
2.With slope correction: A circular plot of 1,000 m
2
(R =
17.845 m) on the slope becomes an ellipse in map plane.
R
1= 17.845 m and
R
2= R
1*cosine = 15.454 m
Corrected Area of the plot = R
1R
2= 866.4 m
2
EpF= 10,000/866.4 = 11.54 => 50*11.54 = 577 trees per ha