-54- to their origin: soft, mixed and hardw:lod types. Results sirjw that stands

Transcription

1 -54- OBSERVATICNS CN RroENERATIOK OF F<XD SPEX:IES FOR M:XlSE IN CLE1\R-ctrr STANOO IN MllSTIOOOCHE P1IRK, C(JEIlEX:: Jean Vall~ Service de l' all'f!ijagerent de la Faune Minist:l!re du Tourism, de la Chasse et de la P&he Shawini!Jan, Quebec. Robert Joyal oeparterent des Sciences biologigues Universite" du ~ A M::lntrehl M::lntrehl, ~ and Richani Couture ojparterent de Chimie-Biologie Universit6 du ~, Trois-RiVikes ()I&ec Abstract: Regeneration offering available food for IlOOse was evaluated in 12 clear-cut stands of different age. Stands were classified acoording to their origin: soft, mixed and hardw:lod types. Results sirjw that stands fran all origin offer a maxi.mrnt of stans in the early stage of the succession, rumely around 5 years of age.

2 -55- The present study is part of a management program for the forest exploitation of Mastigouche Provincial Park in order to maintain an optimal habitat for moose. This new 1500 km 2 park, created in 1971, is situated some 100 km northeast of Montreal. The study area is located in the Laurentian section of The Great Lakes/St. Lawrence forest region (Rowe 1959). The principal plant associations are balsam fir-yellow birch, sugar maple-yellow birch, and black spruce stands. The maximum snow depth in the winter yards sometimes reaches 120 em, but for only a limited time. Generally this factor does not prevent the moose from feeding adequately. The forest has been logged locally since At first, mostly white and red pines and white spruce were exploited, creating suitable habitat for moose. Today, extensive clear cutting of softwood for pulp and intensive use of yellow birch for plywood affect the initial pattern of moose habitat. The region now occupied by the park has always been exploited for hunting moose, whose density is about 4/10 km 2 (Vallee 1973). Since 1973, hunting has been controlled.

3 -56- Besides hunting, there is a growing demand by users of the park for a greater opportunity to see a moose. The moose, therefore, is as v~.uable from an aesthetic point of view as it is for consumption. Even if we know more about the moose's diet, and even if we have a better idea of his habitat, we still lack much data on the forestry practices that maintain his optimal habitat. In other words, we have long known that logging and fires, for example, create proper openings for wildlife. However, we hesitate, when we are dealing with foresters, to provide prescriptions for wildlife management. It might be because easily available literature on the effects of logging on food production tor ungulates is extremely rare for eastern Canada and probably elsewhere other than the works of Telfer (1970, 1972, 1974). An example of the lack of data comes to mind when we evaluate regeneration. Generally, forestry companies have never taken into account the regeneration of shrubs, worrying only about the growth of commercial tree species; the latter, except balsam fir, are not often used by the animals for food, but only as forest cover when the trees reach maturity.

4 -57- CHOICE OF SITES A study of inventory maps of the lumber companies in Mastigouche Park reveals two characteristics. First, most cutover areas were 70 years old when logged, and on the most recent maps about 32% of the study area was still covered by 70-year-old stands, the most important age class. Secondly, since 1950, logging was mostly of the total-cut type, that is, clear cutting in softwood and repeated partial cuts in mixedwood and hardwood. Therefore, we chose total-cut areas where original stands were 70 years old. The standard forest-type classlfication used by the Quebec Forest Service before 1970 was the following; The Softwood type - Where 75% or more of the inventory volume for all species 4" DBH and over is comprised of the softwood species. The Mixedwood type - Where 25% to 74%, inclusively, of the inventory volume for all species 4" DBH and over is comprised of the softwood species. The Hardwood type - Where only l% to 24%, inclusively, of the inventory volume for all species 4" DBH and over is comprised of the softwood species.

5 -58- Within these three forest types, a total of 9 cutover stands, between 5 and 25 years old, were selected. Moreover, a 70-year-old un~isturbed stand was chosen in each forest type. The vegetation inventory was carried out by sampling plots of 20 m by 1 m (1/500 ha) systematically distributed on equidistant lines. In each plot, we noted the species and the diameter of every stem at 0.66 m from the ground. A preliminary sampling was made of each stand in order to determine the number of plots necessary at the usual level of probability (p ~ 0.05). The required number of plots to be collected for all species was then determined by using the formula: n t 2 s2 (E ic)2 where E is the accepted error (10%). All tallied stems do not necessarily represent a winter feeding potential for moose. We have therefore selected the main browse species which make up the diet of this animal.

6 -59- Listoof bttjwse species selected: l m01ultain maple red maple striped maple sugar maple yellow birch white birch willows trembling aspen beaked hazelnut mooseberry appalachian tea wild red cherry m01ultain ash balsam fir (Acer spicatum) (Acer rubrum) (Acer pensylvanicum) (Acer saccharum) (Betula allegpaniensis) (Betula papyrifera) (Salix spp.) (Populus tremuloides) (Corylus cornuta) (Viburnum alnifolium) (Viburnum cassinoides) (Pr=us pensylvanica) (Sorbus americana) (Abies balsamea) The object of this study was to determine the ideal mosaic of cutover / cover / age / dimensions, so that a percentage of the park area could always be repre~ented by this ideal patterns. In this way, the moose population will answer to both consumptive and non-consumptive needs. The first part of the study, presented here, gives the total number of st'ems per hectare p:r-esent after cuts of different age. The second phase, which is presently in progress, concerns determination of the green weight of annual growth according to the type and age of the stands.

7 -60- RESULTS AND DISCUSSION A. Number of stems per hectare In the 4 stands of hardwood origin, the total number of stems of all species varies between 14,750 and 27,100 (Table I). If we take into consideration the browse species only, their number varies between 13,500 and 25,250, the latter being found in 12-year-old cuts. However, as early as 22 years after logging, the number of stems is reduced to the same order as undisturbed stands. We therefore note in Table I that the 22-yearold cut overs and the 70-year-old stands are not significantly different. The 5 and 12-year-old cuts do not vary greatly among themselves, but show a contrast between the 22-year-old cuts and the reference stand. We have found only 2 logged areas that had originated from 70-year-old mixedwood. Here, the total number of stems varied from 14,700 to 34,300 and that of the browse species was between 13,350 and 26,950 (Table II). It was in the 5-year-old cuts that we found the maximum number of stems. In the mixedwood, the number of stems offering available twigs in the cuts is almost the same as in the 70-year-old reference stand, and this as early as twelve years after logging. Therefore, we have not found a significant difference between the reference stand and the 12-year-old cuts.

8 -61- Table I: Characteristics of regeneration in logged areas of hardwood origin. Stands Number of plots Number of stems/ha (all species) Number of stems/ha* (browse species) Hs (a) H (b) H (b) H (a) Table II: Characteristics of regeneration in logged areas of mixedwood origin. Stands Number of plots Number of stems/ha (all species) Number of stems/ha (browse species) (a) (a) Table III: Characteristics of regeneration in logged areas of softwood origin. Stands Number of plots S s 50 S5 50 S12 59 S15 62 S22 55 Number of stems/ha (all species) Number of stems/ha (browse species) (a) (a) * identical letter following the number means a non-significant difference at the 5% level.

9 -62- The total number of stems in the softwood varies from 5, 250 to 23, 950 and for the browse species from 2,750 to 20,350 (Tabl~ III). Once again, it is the 5-year-old cuts that offer the greatest number of stems. Only the 15 and 22-year-old cuts do not differ significantly among themselves. We notice that in the S12' the total number of stems/hectare decreases normally. However, the stem density of the browse species in this stand makes a notable drop. This is undoubtedly linked to the characteristics of the sampled site. There is not much difference, however, between the density of all species and the number of the browse species. This observation suggests that in the first phases of the succession most of the species present are utilized by moose, and this, independently of the origin of the stand. We do note, however, a greater difference in the cuts of softwood origin. If we compare the logged area (from all origin), we note that the cuts which offer a maximum number of stems of browse species - that is, the 12-year-old hardwood, the 5-year-old mixedwood, and the 5-year-old softwood - are those which differ the most from all the others (Table IV).

10 -63- Table IV: Non-significant difference at the S% level between logged areas of all origins Stands Difference non-significant at the S-percent level H s HS H 22 ; M 12 ; SIS; S22 H 12 ; Ss H12 MS HS H22 M M ; 12 S12; S22; H s s M M ; s 12 S12; H22 MS H12 M12 S12; S22; H t H 22 ; Ms Ss Ss HS S12 H ; M 22 s M22 SIS S22; Hs S22 H ; M ; S15

11 -64- The softwood reference stand is an exception, being distinct from the 11 others. The relatively limited number of stands in each age group does not permit us to establish with certitude the exact age of the cut where regeneration is maximum. This would be impossible since regeneration is dependent on the characteristics of the site (Frisque and Weetman 1973). However, the number of stands studied is sufficient to reveal that the optimal age for regeneration in Mastigouche Park tends to be between 5 and 15 years old, according to the origin of the stands. Figure 1 shows the brevity of the period where the number of stems is at its maximum. According to our data, this maximum is situated between 5 and 10 years of age for stands of soft and mixedwood, and between 10 and 15 years of age for the hardwood. Telfer (1972) shows that the 10 to 12-year-old cuts of mixed origin had the greatest standing stock in New Brunswick. Evidently, we would need more observations to confirm or disprove.it, if for example, the cuts of mixed origin still drop to a minimum as early as the age of 12, compared with the hardwood and softwood stands where the decrease in the number of stems is more gradual.

12 -65-30, / "... ",.,... ",,"'" /... ""...: ""\ '."" ".....""... /,'. " 20.' /... ",/~/ ""'" ", ~ \ " /.~.., 10. Softwood Hardwood Mixedwood Fig. l AGE (years) RELATION BETWEEN THE NUMBER OF STEMS / HA OF THE BROWSE SPECIES AND THE AGE OF THE CUTOVER IN THE DIFFERENT STANDS.

13 -66- B. Twig number per stem In order to obtain good results in the second stage of the study, that is, to find the weight of the annual growth of the different cuts, it was important to know the number of twigs present on the stems as well as their average weight according to their diameter class. This time-consuming work is not concluded for all species, but Table V shows results for the two principal species (balsam fir and mountain maple) generally found in the diet of the moose in eastern Canada. The number of twigs per balsam-fir stem increases continuously from 15.5 in class I to in class VI. Their mean fresh weight varies between 0.36 g and 0.57 g without any relation to diameter class. The total weight of the annual growth increases rapidly from a minimum of 5.58 g in class I to more than in class VI. The characteristics of the available annual growth of mountain maple are different. The number of twigs per stem is less important since it varies from only 4.2 to The mean weight of the annual growth shows a greater variation, with higher figures ranging from 0.40 g to almost 1.2 g. However, the maximum weight per stem is about 30.0 g only in classes III and IV. The noticeable decrease in the number of twigs available and in the total

14 Table V: Annual growth characteristics of balsam fir and mountain maple by green weight. Diameter BALSAM FIR MOUNTAIN MAPLE (em) N. twigs/ Mean weight Total weight (g) N. twigs/ Mean weight Total weight (g) stem of twigs (g) per stem stem of twigs (g) per stem , , r 0- " r %

15 -68- weight of class V- is caused by the bulk of the armual growth now being over 3 m in height. Not enough mountain-maple specimens were found in class VI to provide statistics. Of course, more information could be obtained from these data, but a more useful discussion on management will be possible, for instance, only when results from all species are available.

16 -69- LITERATURE CITED Frisque & Weetman, Reproduction 5 annees apres la coupe: 21 aires d'etudes au Quebec. Foret - Conservation, volume 40 (4): pp Rowe, J.S., Forest regions of Canada. Can. Dep. North. Affairs Nat. Res., 71 pp. Telfer, E.S., Relationship between logging and big game in eastern Canada. Pulp Pap. Mag., October # 2: Forage yield and browse utilization on logged areas in New Brunswick. Can. J. Forest. Res. 2: Logging as a factor in wildlife ecology in the boreal forest. The Forestry Chronicle, October: Vallee, J., Inventaire du cervide dans Ie secteur Sud de la Mauricie. Ministere du Tourisme; de la Chasse et de la Peche. Service de l'amenagement de la Faune. 8 p. Mimeo.