No. 110 

1960 

HOW MUCH SCAR1 FICATION FROM SUMMER LOGGING? 

Scarification of the soil creates seedbeds that are 

favorable for the establishment of both paper birch and yellow birch. Logging in the summer often has been recommended 

as a method of obtaining these seedbeds. However, our observations on experimental logging jobs have shown that logging alone does not provide scarification over enough of the 

area to assure reasonably uniform distribution of birch regeneration. 

In a recent cutting treatment in an old-growth northern hardwood stand on the Bartlett Experimental Forest in 

New Hampshire, eight rectangular patches, each 4.0 by 1.7 

chains (2/3 acre), were logged during August. The merchantable material was skidded tree-length, using an HD-5 tractor 

and arch. All other trees down to 2 inches d.b.h. were cut t. and left on the ground. 

Immediately after logging, a survey was made to determine the amount and pattern of soil disturbance. A map 

was made of each patch, showing the locations and dimensions 

of skid roads and trails, large piles of slash, and rockcovered areas. The areas of skid roads where mineral soil 

was exposed were planimetered. The remaining patch area was 

then sampled for seedbed condition and classified as: 

1. Mineral soil. 

2. Humus--where leaf litter had been removed down to the 

humus layer but not deep enough to expose mineral soil. 

3. Natural--areas not disturbed by logging; they still were 

covered by heavy leaf litter. 

4. Other--areas covered by large rocks or boulders. 
For the sampling, a series of lines 24 feet apart was 

run across the width of each patch. At intervals of 12 feet 

along each line an area of 1 square foot was classified according to its seedbed condition. 

Results 

The average area of exposed mineral soil was less 

than 10 percent. By combining mineral soil and humus seedbeds, we found that slightly less than one-third of the 

patch area was disturbed by logging. This one-third was not 

distributed evenly over the patch, but was concentrated in 

and around the skid roads. Some portions of the skid roads 

received heavy traffic, and were almost entirely of mineral 

soil. Many portions, however, had not received sufficient 

traffic to expose mineral soil; most of the humus seedbeds 

were located on these portions. 

In addition to leaf litter, heavy slash was found in 

most patches on portions of the natural seedbeds. This 

slash, in piles 4 feet or more in height, covered an average 

of 13 percent of the total patch area. 

The area in each of the various seedbed conditions is 

shown in table 1. Figure 1 is a composite sketch of the 

eight patches studied, showing a typical distribution of the 

various seedbed conditions. 

SEEDBED CONDITION 

NATURAL 

#-- HUMUS '0~~ 

MINERAL 

Figure 1. --Typical distribution of seedbed conditions. 
Table 1.--Percentage of area in various seedbed conditions 

Discussion 

Item 

Mineral soil provides optimum conditions for the establishment of the birches: it provides a stable moisture 

supply and allows the rootlets to penetrate to this moisture 

source immediately . Other types of seedbeds sometimes act 

as a physical barrier and are subject to higher temperatures 

and to rapid drying. In spite of this, some birch will 

germinate and survive on humus and even on natural seedbeds. 

If moisture, light, and other factors are right, enough may 

survive to produce a well-stocked stand. But these conditions seldom occur, and additional scarification to provide 

a greater exposure of mineral soil almost always will increase the amount of birch. 

Average 9 23 65 3 

Mineral 

If regeneration of birch is the management objective, 

a special effort should be made to scarify a much larger 

proportion of cutting areas than the scant one-third found 

to have been scarified on our surveyed patches. 

--DAVID A. MARQUIS and JOHN C. BJORKBOM 

Research Foresters 

Northeastern Forest Experiment Station 

Forest Service, U.S. Dept. Agriculture 

Humus Natural Other