Herbicides and Their Uses for Alternate Conifer Species - Summer Seminar and Field Tour Recap In mid-July, Wilbur-Ellis Company presented a series of indoor sessions followed by field tours throughout western Washington and western Oregon. We spent about four hours inside discussing forest herbicides and their uses for alternate conifer species (non-Douglas-fir) as well as new developments in vegetation management. Over 160 foresters attended these sessions and new ideas were discussed and shared among our fellow professionals. In the field tours we visited sites of our seedling fertilization experiments, and other sites looking at the reforestation of species such as some of the wealth of information we spoke about and what we learned from other field foresters. Herbicides and Alternate Conifer Species More foresters and their organizations are planting a wider variety of conifer species than ever before. On the west side of the Cascades, Douglas-fir is still king, but with Swiss Needle Cast problems on the coast and some areas inland, we are seeing more and more plantings of cedar, hemlock, noble fir, and valley ponderosa pine. Some forester are planting mixes of Douglas-fir and other species while some are planting entire units with just hemlock or cedar. Since most forest herbicide labels were written in the 1980's and '90s before this trend towards alternate species, we decided to review each product label carefully to look for mention of species other than Douglas-fir. Some labels are very specific to which species it can be used with for site preparation or release. Other labels are very general and just state: "for use on forestry sites". This could cause a problem if you want to plant a different species! During the meeting we handed out a spreadsheet which lists the Forest Chemicals and the status of the tree species on the label. The tables below are updated copies from the seminars utilizing the input of the foresters in attendance. We noted on the spreadsheet if the species was labeled for use for that chemical and included some cautions for problems we and others have seen in the field. Growing Alternate Species: Western Hemlock One could write a masters thesis on the reforestation of western hemlock, but here are some highlights in relation to vegetation management we discussed at the seminars. Even though western hemlock is shade tolerant, it survives better and grows much faster if it receives the benefits of controlling competing vegetation. Full sunlight, good soil moisture, good soil nutrition, and healthy planting stock are all critical in reforestation success. For conifer site preparation we have not seen any problems with planting into sites treated with the common herbicides. For conifer release however, hemlock is much more sensitive than Douglas-fir to Arsenal A.C. and is not recommended or labeled. The Accord ® label and Glypro® label both limit its use in hemlock release to 1 lb. active ingredient (a.i.) per acre and recommends using no surfactant. This reduces the top damage often seen with glyphosate on hemlock, but does of course, reduce the brush and weed control. Western Redcedar Growing cedar has been a challenge for forester due to its attractiveness to deer and elk. Without control of the big game browsing, planted cedar can survive for 10-15 years and never grow beyond waist high. Successful plantations have been grown using good weed control along with aggressive browse control. This spring, Fred Pfund of Starker Forests and I revisited two sites which were planted in 1986 and 1990 exclusively with cedar. I had seen them when they were first planted and not again until this year. The 1986 plantation is now dominated by natural Douglas-fir, which have out competed the planted cedar. The 1990 unit is now 99% western redcedar and has been pre-commercially thinned. Fred said that the lessons of the 1986 unit were applied to achieve greater success in the 1990 unit. The keys to successful cedar regeneration Fred stressed were: do a superior job of site preparation, follow up with good herbaceous weed control and aggressively prevent big game browsing by using repellent. He discovered most of his browsing problems occurred in the fall and winter so repeat application of repellent was necessary. Cedar is very sensitive to Velpar® and normal application rates can kill and injure them easily. Many brush herbicide sprays can cause some browning of the foliage, but they usually grow out of it. Deer Away® repellent can cause foliage damage in the spring, but the new repellent PlantSkydd® has been shown to be very safe on cedar. PlantSkydd® can be applied to the seedlings in the nursery at the packing stage to protect them from initial browse. New growth should be retreated in the spring if you have a spring browse problem in your area. Editor's Note: This copyright information previously published in the Wilbur-Ellis August 2000 Newsletter, Forest Vegetation Management Bulletin, and reprinted with the permission of Wilbur-Ellis.