680 



TIMBER RESOURCES FOR AMERICA'S FUTURE 



less than four growing seasons prior to examina- 

 tion. The standards based on number of seed 

 trees left per acre and those based on proximity to 

 the margin of a group, strip, or stand of seed- 

 bearing trees are given in the preceding tabula- 

 tions. 



Maple-Beech-Birch and Oak-Hickory 

 Type Groups 



Prospective stocking was considered only if the 

 area was cut less than four growing seasons prior 

 to examination. Due to prolific seeding and 

 sprouting ability of the species associated with 

 these types, it was considered that the areas would 

 restock fully unless restocking was adverselj^ 

 affected bj^ cull trees, weed trees, herbaceous 

 growth, slash, grazing, deer browsing, etc. 



Loblolly- Shortleaf Pine Type Group 



Prospective stocking was considered only if the 

 area was cut less than five growing seasons prior 

 to examination. Only pines were accepted as 

 seed trees. The standards based on seed trees 

 and proximity to the margin of a group, strip, or 

 stand of seed-bearing trees are shown in the pre- 

 ceding tabulations. Where seedbeds had been 

 improved by successful prescribed burning, seed- 

 tree requirements were reduced to a minimum of 

 50 percent of those indicated in the tabulation. 



Oak-Pine Type Group 



Prospective stocking was considered only if the 

 area was cut less than five growing seasons prior 

 to examination. On good hardwood sites (site 

 index 50+ for oaks or 60+ for sweetgum and 

 yellow-poplar) only seed trees of desirable species 

 were recognized. On poor hardwood sites, onh" 

 yellow pines were recognized as seed trees. 

 Heavy-seeded hardwoods were not considered as 

 seed trees unless they were within 1 chain of the 

 plot. Prospective stocking standards are shown 

 in the tabulations. 



Effect of Felling Age 



The standards for the proportion of the mean 

 annual growth at culmination attained at various 

 ages or stump diameters are shown in table 90 for 

 all forest type groups except the oak-pine. In 

 this type group, no felling-age factor was applied 

 to hardwoods if the site index on a cutting area 

 was lower than 50 for oaks or hickory, or lower 

 than 60 for sweetgum or yellow-poplar. The 

 rating was then based entirely on the age of the 

 pines cut, and the standard for lobloUy-shortleaf 

 pine (table 90) was used. 



On better sites, the rating was affected by the 

 age of both the pines and hardwoods cut. The 

 rating for pines was taken from the standard for 

 lobloUj^-shortleaf pine and that for hardwood 

 species from the oak-hickory standard. 



STANDARDS FOR THE LAKE 

 STATES REGION 



Forest Type Groups 



The following forest type groups and types were 

 recognized: 



Aspen-paper birch 

 Spruce-fir 



Swamp black spruce- 

 tamaraek-type 



White-red-jack pine 



Jack pine type 

 Maple-beech-birch 

 Oak-hickorv 



Species Classification 



The classification of species by type gi'oups and 

 sites is shown in table 91. 



Existing Stocking 



Table 92 shows the number of trees per acre |jl 

 required for 100-percent stocking. " 



Prospective Stocking 

 Aspen-Paper Birch Type Group 



During the first 2 years after cutting, the fol- 

 lowing conditions were required for a classification 

 of "full stocking": 



1. Thirty aspen stumps per acre (well distributed 



over area). 



2. Eightj^ percent of ground area free of brush. 



heavy sod, cull trees, or other shade. 



3. Sandy loam or better soils. If the soil was 



very light, the examiner made adjustments 

 in line with results in comparable sites in 

 the locality. 



Prospective stocking for species other than aspen 

 in this type group was determined by standards 

 for other type groups. 



Spruce- Fir Type Group 



Other spruce-fir type {upland and swamp 

 phages). — Prospective stocking was considered 

 only if the area was cut less than 5 j'ears prior to 

 examination. Seed trees were recognized only 

 if at least 7 inches d. b. h. for spruce or 5 inches 

 d. b. h. for balsam fir. Twenty such seed trees 

 well distributed over an acre were considered 

 essential to full stocking. 



