Management Guidelines for Riparian Forests 



Management information forindividual sites 

 is based on type-specific habitats (Boggs and 

 others 1990). This leaves concerns over other 

 more general situations. These include headwa- 

 ters management priorities, windthrow prob- 

 lems, stream protection, and regeneration prac- 

 tices. 



Results — Management Information 

 FOR Special Concerns 



Watershed concerns in headwaters areas 

 must be a top priority (for example, ABLA/ 

 CACA, and other wetlands within ABLA/LUHI, 

 MEFE types). The higher precipitation and 

 snowpack of upper elevation headwaters re- 

 quire special attention to protect water quality. 

 Although the streams may be very small, or 

 intermittent, they require at least the same 

 amount of protection regarding sediment pro- 

 duction and transport as larger streams. For 

 basins with a high density of small streams this 

 may require treatment of entire units with the 

 same care exercised in wetlands along streams 

 at lower elevations. 



Windthrow is an obvious problem in most 

 wetlands and along streams. Some of the timber 

 sales audited were actually set up to salvage 

 previous blowdown. Blowdown (actual or po- 

 tential) was specifically identified as a concern 

 on 13 of the 48 sites. Large trees on wetland 

 sites usually have shallow root systems and the 

 soil has little holding strength when water tables 

 are high. An undisturbed stand of large trees 

 along the stream adjacent tocutting units is very 

 susceptible to blowdown, creating unusually 

 high amounts of woody debris in the stream and 

 increased soil erosion potential and streambank 

 damage from upturned root systems. Abrupt 

 edges in stand structures should be avoided. 

 Windthrow risk can be reduced by several tech- 

 niques, considered in combination with other 

 objectives. Clearcutting removes the potential 



of windthrow from the immediate site and trans- 

 fers the problem to adjacent stands. Where 

 clearcutting is used to meet other objectives, a 

 treatment of adjacent stands (or salvage of ex- 

 pected blowdown) should be planned. Light 

 partial cutting (removing less than 30 percent of 

 the basal area) has been suggested for wetland 

 sites. This can be accomplished with single tree 

 or group selection harvesting, depending on the 

 species composition and structure of the stands. 

 One suggestion was to select trees for removal 

 that were the most susceptible to windthrow. 

 Another suggestion was to use partial cutting, 

 leaving windfirm trees on adjacent upland sites, 

 to buffer the effects of wind on trees in the 

 Streamside Management Zone. Local experi- 

 ence is especially valuable for interpreting 

 windthrow risks. General prescriptions for 

 Streamside Management Zones are not the an- 

 swer. Rather, we recommend that windthrow 

 risks and appropriate management of those risks 

 be addressed specifically in a silvicultural pre- 

 scription prior to harvesting activities. 



Woody debris has been recognized as an 

 essential component of stream structure in sev- 

 eral kinds of streams. Potts and Anderson ( 1 990) 

 report on the importance of natural and logging 

 woody debris in small stream channels. Some 

 organizations are developing fairly rigid crite- 

 ria for the leaving of trees along the stream for 

 future woody debris recruitment. However, the 

 potential of post-treatment blowdown may ne- 

 gate the objective. The suggestion of selective 

 harvesting of the high windthrow risk trees and 

 leaving trees of various sizes that are more 

 windfirm should be considered (as above). 

 Again, we caution against generalized prescrip- 

 tions. Rather, we recommend that woody debris 

 recruitment be addressed specifically in a 

 silvicultural prescription prior to harvesting 

 activities. Work is also needed to define desired 

 kinds, amounts, and timing of woody debris for 

 different kinds of streams. Furthermore, the 



Page 94 



Flathead Basin Cooperative Program Final Report 



