116 RICHARD SCHMITT 



These excellent silvicultural qualities are, however, partly off- 

 set by less desirable ones, as follows: 



1. The tree develops a shallow root system and for this reason is 

 unable to penetrate heavy soils. This may be the cause of the "crisis 

 after forty years of growth" (Hesse, 1954). This confined root system 

 often cannot support the tree, and windfall is not uncommon (Wappes, et 

 at., 1935; Penschuck, 1937). 



2. The relatively high water requirement is another limiting factor. 

 White pine develops poorly on the hot, dry slopes and ridges of the 

 Rhenish Schist Mountain Range (RUdesheim) . The tree becomes dwarfed 

 under more arid conditions (Misson, 1962) . 



3. Another limiting factor comes into play when the tree is planted 

 in localities having a short growing season. The first sign of this 

 problem is that there is no decomposition of litter--only raw humus is 

 formed (Wappes et al. s 1935). 



4. Serious enemies are game animals (Eckstein, in press). The 

 honey fungus Armillaria mellea Sacc. (Rohmeder, 1957; Rossmassler, 1954; 

 Rubner,1925; Eckstein, 1966), and, of course, the blister rust (Mulder, 

 1960) . Several Pissodes species heavily damage seedlings and stands of 

 sapling and pole size (Eckstein, in press). Needle cast fungi are less 

 important (Sperber, 1959). 



5. In mixed stands and pure ones with open canopies the trees produce 

 very little clear lumber (Hoemann, 1928). They must be pruned if good logs 

 are desired. 



GROWTH AND YIELD OF EASTERN WHITE PINE 



P. strobus makes rapid height growth (Holubcik, 1968b). According to 

 the yield table (Eckstein, in press), maximum growth is reached at the age 

 of 15 to 20 years. It will outgrow all European forest tree species and 

 keep a dominant position for more than 80 years. Figure 1 (from Eckstein) 

 shows the height growth of the average sample white pine for 5 site 

 classes, compared with growth of larch (Larix deeidua Mill.) for site 

 classes I and III, and of beech (Fagus silvatica L.) for site classes I, 

 III, and V. 



The number of stems per unit of area decreases rapidly with age. On 

 the best sites, a fully stocked stand at age 80 years will consist of 

 only 200 stems per ha (= 80 per acre) . The average good-site tree will 

 then have a 50 cm d.b.h. , but if white pine is planted as a nurse tree on 

 hot and dry slopes only 27 cm d.b.h. will be attained. Scotch pine 

 requires 200 years to grow to these dimensions, and Norway spruce 

 140 years (Eckstein, in press). 



The form factors of the stems are more than 10% better than those of 

 Scotch pine, but the taper of larger trees is greater than that of Norway 

 spruce (Eckstein, in press). 



r 



Given proper management, according to Eckstein (in press) , white pine 

 stands at age 80 have a basal area of from 26 to 40 square meters per 

 hectare (= 110 to 170 square feet per acre) . 



