Article Figures & Data
Tables
- Table 1.
Species, number of study trees and control trees, location, average diameters and percent of crown left after topping.
Species Study area Number of topped trees Number of control trees Average diam. of topped trees Average diam. of controls Percent of crown left after topping cm cm Beech, American Maryland 30 30 19.6 23.9 50.4 Hickory Maryland 28 28 20.5 16.9 69.2 Oak, chestnut Pennsylvania 30 30 30.5 30.0 52.4 Oak, northern red Pennsylvania 30 30 37.4 38.9 57.2 Oak, white Maryland 30 30 24.3 21.3 48.3 Pine, Virginia Maryland 30 30 18.4 18.0 62.7 Sweetgum Maryland 24 24 19.7 26.2 39.3 Sycamore Maryland 7 7 43.2 52.7 36.1 Yellow-poplar Pennsylvania 30 30 34.5 29.0 45.3 Crown Class Species Dominant Co-dominant Intermediate Overtopped Beech, American 50 37 37 — Hickory 43 53 37 18 Oak, chestnut 116 102 107 76 Oak, northern red 110 107 99 — Oak, white 56 56 27 35 Pine, Virginia 41 30 12 — Sweetgum 64 63 26 05 Sycamore 85 43 — — Yellow-poplar 131 120 79 114 Average 77 68 47 28 - Table 3.
Average basal area growth (in cm2) by species for five-year period before and after topping for Maryland study area.
Topped trees Control trees Species 1967-1971 1972-1976 1967-1971 1972-1976 Beech, American 40 50 70 60 Hickory 40 40 30 30 Oak, white 60 60 60 70 Pine, Virginia 50 40 50 40 Sweetgum 50 40 70 80 Sycamore 170 190 160 190 Average 50 50 60 60 - Table 4.
Average basal area growth (in cm2) by species for four-year period before and after topping for Pennsylvania study area.
Topped trees Control trees Species 1969-1972 1972-1976 1967-1971 1972-1976 Oak, chestnut 80 80 70 70 Oak, northern red 120 110 120 130 Yellow-poplar 240 210 220 180 Average 170 130 130 130 - Table 5.
Multiple regressions and coefficients relating basal area growth since topping (G) with percent of crown remaining after topping (H) and diameter breast high (D), and levels of significance.
Species Multiple regression equation Multiple regression coefficient Simple correlations (r-values) H,G D2,G D2,H Beech, American G = 0.0242+ 0.00032D2 + 0.00008H 0.69** 0.004 0.685** −0.048 Hickory G = 0.0286 + 0.0001 8D2 − 0.00002H 0.62* −0.049 0.624** −0.071 Oak, chestnut G = 0.0035 + 0.00019D2 + 0.00086H 0.59** 0.458** 0.514** 0.347 Oak, n. red G = 0.0324 + 0.00034D2 + 0.00068H 0.54** 0.146 0.545** 0.248 Oak, white G = 0.0425 + 0.00012D2 − 0.00007H 0.48* 0.012 0.483* −0.040 Pine, Virginia G = 0.0431 + 0.00049D2 − 0.00039H 0.76** −0.179 0.690** 0.206 Sweetgum G = 0.0198 + 0.00037D2 − 0.00003H 0.77** −0.057 0.775** −0.034 Sycamore G = −0.083 + 0.00054D2 + 0.00179H 0.95* −0.175 0.935** −0.353 Yellow-poplar G = 0.0365 + 0.00031 D2 + 00339H 0.57** 0.521** 0.256 0.051