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the area of the crosssection of a tree at breast height (about 4.5 feet above ground) usually expressed in square feet. Often used to measure density. Can be used to describe a single tree or the sum of an entire area.
{categorization=ecology}
some stuff to be added
here are some maths for forestry notes, if someone has time they can use them and add them in here with links:
Volume=〖DBH〗^2*π/4*H*Formfactor +/ 10% Volume= 〖DBH〗^2/1000 +/ 30% DBH = PBH/π Cylinder r = 0 Paraboloid r = 1 Cone r = 2 Neiloid r = 3 g_x=p*x^r Tree Height Geometry Trigonometry b/((ab))= B/((AB)) a:b=A:B H=D*(tan〖( α)+tan〖( β))〗 〗 Apparent Height h^'=h_uph_down
Real Height h=h^'*〖Cos〗^2 (α) Standard Deviation (s, sx, SD) also called quadratic mean and RMS SD=√((X┴ )^2(X┴ )^2/n)/n Population Standard Deviation (s, sx, SD) SD=√((X┴ )^2(X┴ )^2/n)/(n1) IT IS REPORTED WITH THE MEAN AS X┴±S_X X┴ = arithmetic mean (the mean of the sample) μ = true mean (the mean of the whole population) Standard Error (SE, S_(X┴ )) S_(X┴ )=〖S_X〗_ /√n Confidence Interval CI=n=(SX/(S X┴ ))^(2 )*((C%X)/(C%X┴ ))^2
r_"α" =(r*h)/(Cos α)
FIXED AREA PLOT BlowupFactor 〖BF〗_ha=n/〖ha〗_rep = (10 000)/〖Area〗_plot 10 000=1ha So 1 tree in the plot represents 10 000 〖Area〗_plottrees/ha 1m³ within the plot represents 10 000 〖Area〗_plotm³/ha ANGLE COUNT BAF = ((50 * DBH)/R)^2 LEADS TO R=(50*DBH)/√BAF
Basal Area of a Tree is the area of a given section of land that is occupied by the crosssection of tree trunks: BA = DBH²*π/4 (NB for DBH in cm BA=0.0000 7854 *DBH²) result in m² per ha The basal area of a forest stand can be found by adding the basal areas (as calculated above) of all of the trees in an area and dividing by the area of land in which the trees were measured. The plot area big enough for the tree to be counted is A=R²*π So the basal area density is the BAF
BAF[m²〖ha〗^(1) ]=10 000*ba/A=10 000*(DBH^2*π/4)/((DBH/(W/L))^2*π)=(10 000)/4*(W/L)^2=((50*W)/L)^2 Each tree in ACS represents the same BAF m² per hectare. Represented number of trees
n_rep=BAF/BA=BAF/(DNH²*π/4)
Represented volume V_rep=n_rep*v_tree=BAF/BA*BA*h*ff=BAF*fh — Preceding unsigned comment added by 141.244.80.133 (talk) 18:43, 21 January 2013 (UTC)