Vegetation Control Treatments to Favor Naturally Regenerated Betula alleghaniensis Saplings Following Seed-Tree Cut: Sapling Monitoring Two Years after Treatment Daniel Bouffard, 1,2 Philippe Nolet, 1 Sylvain Delagrange, 1,3 Franc xois Lorenzetti, 1,3 and Stephen Yamasaki 1,3 Abstract Control of competing vegetation is recommended to ensure successful Yellow birch (Betula alleghaniensis Britton) regeneration within juvenile stands that do not sustain high enough sapling densities of this species. Four contrasting vegetation control treatments were tested to determine their effect on the growth and vigor of eight- year-old B. alleghaniensis saplings regenerating after final cutting of a shelterwood seed cut. Vegetation control treatments were TC (total circular removal), PC (circular removal of codominant competing vegetation), TS (total semicircular removal on 180° section), and NC (no vege- tation control). Two years after treatment application, diameter growth significantly improved in response to vegetation control treatments, whereas sapling height growth did not. This pattern of biomass allocation was directly related to sapling etiolation, which increased with decreasing severity of vegetation removal. As a result, application of vegetation control, especially TC and PC treatments, was valuable in reducing signs of stress in sap- lings. However, increasing the severity of vegetation removal also made saplings more conspicuous to herbi- vores, which increased browsing, especially in the TC and PC treatments. Browsing was sufficient in some plots of the TC and PC treatments to overcome the vigor and diameter growth enhancements observed when browsing was negligible. In contrast to the TC and PC treatments, the TS treatment kept browsing very low while largely removing competition. The results suggest that B. alle- ghaniensis saplings established after final cutting of a shel- terwood seed cut do take advantage of vegetation control treatments, but the decision to apply these treatments must include consideration of local herbivore population densities. Key words: deer browsing, etiolation, saplings, vegetation control, Yellow birch. Introduction Among economically important hardwood species, Yel- low birch (Betula alleghaniensis, Britton) is one of the most valuable found in the forests of northeastern North America. However, since the beginning of twentieth cen- tury, reports indicate a proportional decrease of B. alle- ghaniensis in favor of more shade-tolerant species such as Acer saccharum, Marsh. (Nolet et al. 2001b; Bouffard et al. 2003). Establishment and early survival are considered the most important factors limiting regeneration of B. alle- ghaniensis (Erdmann 1990). Poor establishment may be the result of diminishing seed sources caused by a long his- tory of selective cuttings of vigorous seed producers (Nolet et al. 2001a) and the general practice of winter harvesting, which avoids the soil disturbances needed for germination of this species (Houle 1992). Moreover, low survival and growth rates of B. alleghaniensis have been attributed to the diminishing occurrence of large canopy openings, as compared to previous decades, because of better fire control (Woods 2000). The extensive use of par- tial cutting (MRNQ 1998), which results in low light levels in forest understorey, has already been associated with the lack of B. alleghaniensis regeneration success (McClure et al. 2000). One opportunity to manage B. alleghaniensis in Canada is the use of the seed-tree method in which a large proportion of trees are removed (i.e., the creation of large openings), leaving a small number of seed-bearing trees of a desirable species. The uncut trees are antici- pated to be the main source of seed for establishment of natural regeneration and are generally harvested in a final cutting. Within juvenile stands with low B. alleghaniensis sapling densities, control of competing vegetation has 1 Institut Que ´be ´ cois d’Ame ´ nagement de la Fore ˆ t Feuillue (IQAFF), 58 Rue Principale, Ripon, QC, Canada J0V 1V0 2 Address correspondence to D. Bouffard, email dbouffard@iqaff.qc.ca 3 Universite ´ du Que ´ bec an Outaouais (UQO), C.P. 1250, Succursalle Hull, Gatineau, QC, Canada J8X 3X7 Ó 2007 Society for Ecological Restoration International DECEMBER 2007 Restoration Ecology Vol. 15, No. 4, pp. 679–687 679