We begin this review of the literature on clearcutting with white-tailed deer because this species has been thoroughly researched and its needs are perhaps the best known of any game animal in the United States. Clearcuttings have been found to enhance deer habitat in most regions, even in the snowbelt portions of the northcentral and northeastern states, providing that nearby shelter against cold winter winds is available (Verme 1965, Krefting and Phillips 1970, Newton et al. 1989, Hughes and Fahey 1991).
Most studies indicate that the first few years after clearcutting, deer foods (succulent stems of woody plants, forbs, and grasses) increase to their highest level of abundance and availability (Martin et al. 1955, Halls and Crawford 1960, Schuster and Halls 1963, Ripley and Campbell 1960, Murphy and Ehrenreich 1965, Harlow et al. 1966, Harlow and Downing 1969, Crawford et al. 1975, Hunt et al. 1976, Blair and Brunett 1980, Hurst and Warren 1981, Stransky and Halls 1981, Smeins and Hinton 1987). Other beneficial changes include short-term increases in the nutrient values of deer foods (Thill and Morris 1983, Thill et al. 1990, Hughes and Fahey 1991), larger and heavier twigs (Hughes and Fahey 1991), and in some vegetation types, increases in fruit production of certain shrubs (Harlow et al. 1980).
There are some regional differences in the effects of clearcutting on the duration of choice deer foods. For example, in Maine, where the growing season is short, woody browse remains available to deer up to 9 years (Newton et al. 1989), while plants can grow out of reach of deer by the 4th or 5th growing season in rich cove sites of the Southern Appalachians (Harlow and Downing 1969). In east Texas, Blair and Brunett (1980) reported that browse production was highest 2 years after logging, declining thereafter. Seven years later, forage production had declined by 52% and deer had begun browsing pine needles and other non-preferred species.
Most studies have found that deer use clearcuts throughout the year (Harlow and Downing 1969, Cushwa et al. 1970, Blymer and Mosby 1977). However, Wentworth (1989), Wentworth et al. (1990a, 1990b), Wentworth et al. (1992), and Ford et al. (1993), in the Georgia and North Carolina mountains found little winter use of browse in clearcuts. Since clearcutting removes mature acorn-bearing oaks, these authors contended that clearcutting was detrimental because it deprived deer of a needed winter food source. Harlow and Downing (1969) concluded, however, that since more than 90% of the Southern Appalachians are in timber stands 20 years and older, all relatively devoid of deer forage during the winter, more forage-rich cuttings, not less, would be desirable. They believed that without forest disturbances deer become overly dependent on acorns, a food source that often is unreliable.
Another consideration pointed out by Crawford et al. (1975) is the long period of time between most regeneration cuts. Following canopy closure, a decade or two after clearcutting, the forage supply declines and remains scarce until another regeneration cut is made. To avoid such a feast or famine situation, an even flow of deer foods can be maintained by making clearcuts smaller and more frequent. Periodic thinning or other intermediate disturbances also would be beneficial.
Clearcutting often is followed by other practices which facilitate regeneration, control competing vegetation, and increase growth rate. Later in the life of the stand, following canopy closure, intermediate activities such as cleaning and thinning stimulate deer forage production.
a. Site Preparation
Site preparation usually is required when stands are converted to other species. Intensive site preparation often is used in pine-hardwood and upland hardwood forests when they are converted to slash or loblolly pine plantations, primarily in the Coastal Plain and Piedmont regions of the South.
Mechanical site preparation generally increases forage for deer, including winter foods. McKee (1972), Hurst and Warren (1980), Bell et al. (1981), and Locascio et al. (1990) compared quantities of forage biomass after performing a variety of mechanical site preparation practices. All studies indicated that, regardless of the type of treatment(s) (chainsawed residuals, sheared and chopped, roller chopped, bedded, mist-blown and tree-injected, tree crushed and burned) or the time of year, the treated areas had significantly more deer forage than did the adjacent mature pine stands. Bell et al. (1981) also found that following site preparation and bedding, shrubs prevailed by the fifth year and remained so through the tenth year. Copeland (1988) found large increases of deer forage (grass, forbs, vines, and woody plants) on 1- and 2-year old loblolly pine plantations in Mississippi. The sites were clearcut, site prepared (sheared, raked into windrows and burned, disked and bedded) and aerially sprayed with hexazinone two months after planting.
Some studies have shown herbicides decrease forage immediately following application, while others, where burning was used, have shown overall increases. Miller et al. (1989) and Blake and Hurst (1987) found that chemical treatments temporarily (1 to 2 years) reduced total production of forbs and woody vegetation. On the other hand, Stransky and Halls (1976, 1978) found forage peaked the first growing season after a clearcut and burn and that it remained steady for 3 years. On control plots (no site preparation), forage yields required 2 years to reach a peak due to the competition of woody plants. Burning also resulted in forage with a higher nutrient content. In northern white cedar winter deer yards, Verme and Johnston (1986) found an increase in number of cedar stems on burned plots following clearcutting. Fruit yields were higher on control and burned plots than on those subjected to mechanical treatments (Stransky and Halls, 1980).
Few, if any, plant species are totally eliminated from a stand that is site prepared. However, species composition is altered in some cases; e.g., to favor grasses. Conde et al. (1980), in studies in north Florida, found that no commonly occurring plants indigenous to uncut, mature, second-growth stands were eliminated by site preparation. In another study, Lewis et al. (1984) found that for the first 3 years after timber harvest, site preparation resulted in improved forage for deer and cattle compared to uncut stands. Bell et al. (1981) found that following site preparation and bedding, grasses dominated during the second year. In the sandhills of central Florida, Beckwith (1964) noted that removal of from ½ to ¾ of the native plant cover from plots 1 mile square increased use of plots by deer. Almost complete removal of vegetation over an entire plot resulted in a pronounced reduction in deer use.
Once canopy closure occurs, whether the stand is young or mature, many shade-intolerant species in the understory are eliminated or reduced in abundance, decreasing the value of the stand for deer. Several studies have been conducted to determine if thinning, by letting in more light, will restore production of these forages. All such studies, regardless of forest type, indicate that thinning increases the number and availability of deer food plants (Knierin et al. 1971, Harlow 1976, Beck and Harlow 1981, Dickmann et al. 1987, Tappe et al. 1992). One study of thinning at 5 year intervals in loblolly pine plantations found that midstory density increased directly with intensity of thinning (Blair and Enghardt 1976). Fertilization, when applied in combination with thinning, also enhances deer forage (Hurst et al. 1982).
Cleaning also can increase forage production. In an 11-year-old hardwood sapling stand in the Southern Appalachians (the result of a clearcut), ground level vegetation was only 3 lbs/ac. After an intensive cleaning, canopy cover was substantially reduced and deer forage subsequently increased to 81 lbs/ac on the upper slopes and 800 lbs/ac on the lower slopes (Della-Bianca and Johnson 1965).
Almost 90% of the studies we examined indicated that clearcuttings and associated practices enhanced habitat throughout the year for deer, while 10% (all by the same group of investigators) found that clearcutting is of little value to deer during the winter. The early advantage of clearcuts for deer may be negated if there is a long interval between regeneration cuts, if there are no intermediate treatments such as thinnings and cleanings, or in the snowbelt regions if adequate shelter is not left for deer during cutting.
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