A Silvicultural" Evaluation of Four Methods of Marking

Second-growth Northern Hardwood Stands

J

Second-growth northern hardwood stands occupy were a makeshift means of preventing destructive

an important segment of the commercial forest land cutting and that therules must be relatively compliof Upper Michigan andnorthern Wisconsin. The cated to obtain-results comparable with silvicultural

size- and age-class distributions and species compo- marking.

sition of these stands vary considerably, but under This Note compares four methods of marking or

all conditions most of the trees are highly defective designating the trees to be cut or to be left in the

or poorly formed or of an undesirable species. Forest first commercial thinning and improvement cutmanagers recognize the need for early thinning and tings of second-growth northern hardwood stands in

improvement .cuttings but havehitherto been re- the Lake States. Because of the few trees with

luetant to do noncommercial cutting. Now, however, potential high quality (Eyre and Zillgitt 1953, Hurd

not 0nly are there active noncommercial operations 1960), any efficient stand improvement measure

on the National Forests of the region, but also the should favor the growth and development of these

-use of dense hardwoods for pulpwood is making trees. It should also yield adequate returns to cover

cuttings economically feasible at a much earlier age the costs of cutting and marking.

than, waspreviously possible.

in the Lake States the cut of northern hardwood The study._In all four techniques described below,

stands has generally been controlled by marking the the residual density aimed for was 80 square feet

individual trees to be removed. In old-growth and of basal area per acre in trees of intermediate crown

regulated stands this management expense is offset class and above.

by current income. In young second-growth stands, 1. Marking by individual tree selection. The trees

• however, the ,return from the first cutting tends to to be removed were selected and paint marked.

,. be submarginal because of the low value of the 2. Setting a diameter limit from above. All trees

products removed and the greater expense of exam larger than the minimum diameter needed to leave

,, ining, and marking a large number of trees. On large 80 square feet of basal area were designated for

ownerships, moreover, the time requirements could cutting.

conceivably place an impossible demand on the tech- 3. Setting a diameter limit from above with

nieal manpower available, good growing stock marked to leave. All trees which

There are other possibilities for preparing these met the specifications as good growing stock (adapted

stands for cutting. The simplest and cheapest would from Arbogast 1957) were paint marked to leave.

be a diameter-limit designation; but in northern As in Treatment 2, trees larger than the minimum

hardwood stands the dollar yield is governed more diameter were designated for cutting.

by species and quality than. by fiber production. 4. Setting a diameter limit from below with good

Other suggested methods involve variable diameter growing stock marked to leave. This technique is

limits for different species, the retention of set num- similar to Treatment 3 except that the trees smaller

bers Of trees within broad diameter classes, mechan- .than a maximum diameter were designated for

ically app!ied spacing factors, and similar rules which cutting.

the logger is expected to follow. Taylor (1946) ana- Test areas were established in four widely sepalyzed and compared the tree-selection method with rated second-growth stands in Upper Michigan.

three other marking procedures in second-growth Each stand was typical of it_ geographical location

Allegheny. hardwoods. He concluded that the rules and needed a thinning and improvement cut. Without

' ,..

MAINTAINED IN COOPERATION WITH THE UNIVERSITY OF MINNESOTA
markets for hardwood pulpwood the returns would The residual densities for the diameter-limit technot have covered, the-cost of the cuttings, niques differed by as much as 8 square feet per

acre from those resulting from the selection markThree of the stands were essentially uneven-aged ings. The differences are not considered critical for

and had densities between 101 and 112 square feet the silvicultural evaluation.

of basal area per acre. These were stocked with a 

scattering of large and highly defective sawtimber Results and evaluation.raThe number of crop trees

trees left on the area at the time of the original cut- ranged from 8 to 28 per acre and averaged 17. This

tings, some small sawtimber trees that developed is similar to the results obtained by Hurd (1_60)

from the poles of the original stand, and smaller in Wisconsin. The species distribution of the crop

.trees that became established following the cutting, trees closely followed that of the stand as a whole.

The fourth stand (136 square feet per acre) origin- Of the 288 crop trees, 45 percent were sugar maple,

ated after a clear cut for charcoal wood and was 42 percent were red maple, and 13 percent were

heavily stocked to poles; 88 percent of the trees were yellow birch, basswood, or beech. Their diameters

between 5 and 9 inches in d.b.h, ranged from 4 to 14 inches, with 94 percent less than

The tests involved no 'cutting, and all techniques 9.6 inches d.b.h. Five percent were in the intermedi-

_ were applied in .the same 4-acre plot. The plots ate crown class, 75 percent were codominants, and

were first marked on the individual tree-selection 20 percent were dominants.

" method by a crew of two foresters experienced in Treatment effectiveness was judged mainly by the

northern hardwood marking for that particular area. 1 degree of release that would have been given the good

Next, the good growing stock was marked to leave; growing stock. The degree of release was estimated by 

the same 2-man crew of resoarch foresters did this the number of adjacent trees of intermediate crown

on all areas because foresters experienced in this class or better marked around each Crop tree by

type of marking were not available in all locations, each cutting method. These data are shown in

The diameter limits were then set to leave the desired table 1.

residual density. These were based on a 100-percent The basis for comparing results is this" Judicious

cruise of all trees of intermediate crown class and thinning of northern hardwood poles generally calls better. : for the removal of one or t_o, and occasionally three, __.

Under the selection method the three uneven-aged competitors. Further release increases the likelihood

stands weremarked to 71, 75, and 77 square feet of of persistent epicormic shoots and sunscald injury.

basal area per acre and the dense pole stand to 100 On the other hand, no release means no alteration of the growth of the desirable trees. (,Some trees,

square feet. The latter residual density is considerably

higher than recommended, but it was considered de- of course, need no release---for example, those with

sirable because of the diameter distribution and gen- full and vigorous crowns.)

erallyvigorous crowns. This method of evaluation has some obvious

weaknesses. Mainly, which trees are cut is often more

Basal area (square feet) important than h,ow many. Nevertheless, the results

in study area_ were so clear that a complicated evaluation seemed

unnecessary. We think that, upon studying the data, ' Item 1 2 3 4

most hardwood managers will agree with the con-

, Before marking . 112 116 101 136 clusions.

After-marking by" The diameter-limit designations left the crop trees

Selection 77 75 71 100 in highly contrasting environments. In both of the

DBH limit from above 82 80 74 92 diameter-limit-from-above methods, more than 50

DBH limit from above percent of the crop trees would have had no release

plus crop trees 78 80 74 '94 (table 1). On the other hand, in the diameter-limitDBH limit from below from-below method 54 percent had four or more

plus crop trees 79 82 75 94 adjacent trees designated for cutting. This release

would have been far too severe for quality increment.

When marking from above, it made little differ1 The author is indebted to the following for their assist- ence whether the crop trees were marked. Most of

ance in locating, cruising, and marking the study areas: them were less than 9 inches d.b.h, and therefore had

Clark Lebo and ]ohn Walstrom, Calumet-Hecla, Inc.; little effect on limits which were 10 inches or above.

Goodman derson, Phi Lumber Uip .Iaqu Division, ith, Mal Calumet, colm McIver, Mich.; and andLeRonichard An- Actually, it would have been impractical to mark

Ruppenthal, U.$. Forest Service. the crop trees because only 5.2 percent would have

°
°

- Table 1._Degree of release of crop trees by marking technique

_.

Number of ad:jacent trees marked for cutting

Marking technique 0 1 2 3 4+

(Percent of crop trees) 

..

Selection 15 29 33 16 7

DBH limit from above 51 34 12 3 0

DBH limit from above

plus crop trees 53 35 10 2 0

DBH limit from below

plus crop trees 2 10 14 20 54

e J

been cut. On the other hand, if the crop trees had this manner ranged from 76 to 82 percent even

not been marked in the diameter-limit-from-below, though the marking was done by four different

more than half of them would have been cut. crews and previous to the marking of the good

growing stock. The basic reason for the results in the diameterlimit marking is that trees of like size tended to grow

in groups. Thus, either most of the group would Time requirements.--The time required to prepare

have been cut or few or none would have been cut. the stands for cutting was recorded on three of the

.Moreover, the good growing stock also tended to be study areas. The small sample and the study con-

'in a group of like-size trees. This environment may ditions rule out absolute time requirements, but the

O a necessity development trees good results indicate crop tree marking (0.48 manbe for the of of that

quality in unregulated northern hardwood stands, hours per acre) can be almost as time consuming

Trees that become dominant early generally develop as marking the trees to cut by the selection technique

coarse branching characteristics. On the other hand, (0.61 man-hours).

trees not reasonably free to grow in height will set

low crowns. In both cases, natural pruning will be In both methods all trees in the stand must be

slow. examined; apparently this tends to offset the advantage of marking the much smaller number of

Another objection to the diameter-limit cuttings trees classified as good growing stock.

is illustrated by the diameter distribution of the cut

and leave trees. In the cuttings from below, the The diameter-limit designations also require a

maximum diameter of the trees to be cut varied from cruise to establish the cutting diameters that would

6_0 tO 7.6 inches. This size tree is not likely to attract leave the desired residual stand density. The evalua-

- 'competen t cutter_. In the diameter-limit-from-above, tion here was based on 100-percent samples, but a

on the other hand, 0nly sawtimber trees would have partial-cruise technique was also tested. The tech-

' been cut. In the' stand heavily stocked to poles, 100 nique employed systematically spaced point samples

percent of the trees above 9.6 inches would have for estimating total basal area per acre, and a tranbeen removed whereas the selection cut would have sect tally between points for estimating the diameter

removed only 21 percent. Although many of the and species distribution. The sample points gave

iarger tre_s in the other stands were marked in the good estimates of the average stand density (the

selection method, skillful manipulation of the har- largest discrepancy was 6 square feet per acre), but

vesting of the remainder would help finance the the transect tally gave generally unsatisfactory estiseries of cuttings required to develop a productive mates of the diameter distributions. Undoubtedly

forest. " , more efficient cruising techniques could be devised, 

but a fairly intensive sample probably would be reThe selection marking clearly created the best quired.

environment for the future growth and development

of the good growing stock. Of the crop trees 78 per- The diameter-limit-from-above without marking

cent had between one and three adjacent trees cut. crop trees would naturally be the most economical

For the four study area_, the crop trees released in method of preparing the stand for cutting. The only

.
task would be a cruise to establish the cutting diam- LITERATURE CITED

eter. However, the -land manager would have to A_OOAST,CARL,JR. 1957. Marking guides for northern

accept the release of only half the crop trees and hardwoods under the selection system.U.S. Forest Serv.,

the other unfavorable features of this system. Lake States Forest Exp. Sta., Sta. Paper 56, 20 pp., illus.

EYRE, F. H. and W. M. ZILLOITT.1953. Partial cut- 

In summary.:--Comidering the silvicultural aspects tings in northern hardwoods in the Lake States. U.S.

and the physical application of the techniques, any Dep. Agr. Tech. Bull. 1076, 124 pp., illus.

control other than marking the individual trees to be Hum_, E. S. 1960. Let's look at our hardwood forests.

cut would be hard to justify if the management goal Tin_ber Prod., Mich. and Wis., 16(6): 6-7.

is the production of high-quality saw logs. The TAYLOR,R.F. 1946. A comparison of silvicultural markforester must evahiate the requirements of each tree ing and cutting px'actice rules in a northern hardwood

rather than those of the stand as a whole, stand. J. Forest. 44: 41-46.

J

July 1966 RODNEVD. JACOBS

Associate Silviculturist

\

, 

°