Overstory and understory competition affect underplanted eastern white pine

Content Provider	Semantic Scholar
Author	Smidt, Mathew F. Puettmann, Klaus
Copyright Year	1998
Abstract	The importance of canopy and understory competition on white pine (Pinus strobus L.) seedlings was evaluated in stands with shelterwood treatments. We sampled 20 stands in north-central Minnesota that were underplanted with white pine 3 to 10 years before sampling. We grouped the stands with various canopy and understory treatments into 6 stand types based on residual canopy composition. The effect of the shelterwood treatments, i.e., residual basal area and understory cover on white pine seedling growth varied significantly among the stand types. Lowering basal area had a greater positive impact on seedling growth when shade tolerant softwood species, especially balsam fir (Abies balsamea (L.) Mill.), were present in the canopy. Where shade tolerant softwood species were absent, the white pine seedling growth increased only slightly or not at all in the presence of lowered residual basal area. We hypothesize that the exclusion of the understory by a shade tolerant midstory, indicated by the presence of balsam fir, prior to shelterwood treatment created favorable conditions for white pine in the understory following the shelterwood treatment. The results suggest that shelterwood treatments on mesic, more productive hardwood sites should be linked to stand development stages where the understory is suppressed, e.g., following development of a shade tolerant midstory or during the stem exclusion phase. This method should complement present shelterwood prescriptions for drier, low quality hardwood sites. This research indicates the importance of evaluating both vertical structure and site quality prior to designing white pine shelterwood treatments.
Starting Page	137
Ending Page	150
Page Count	14
File Format	PDF HTM / HTML
DOI	10.1016/S0378-1127(97)00278-8
Alternate Webpage(s)	http://www.cof.orst.edu/cof/fs/kpuettmann/FEM%20105%201998.pdf
Alternate Webpage(s)	https://doi.org/10.1016/S0378-1127%2897%2900278-8
Volume Number	105
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article