For example, Douglas-fir has considerable genetic variation among populations in different locations and has 16 zones in western Oregon under the new system. Pacific Northwest tree species have different amounts of genetic variation among populations. Research and experience show that the wider seed movement allowed by the new seed zones does not pose a reforestation risk from planting maladapted seedlings. The newer, somewhat larger seed zones developed in the 1990s (Figures 1b-d) are species-specific and based on more recent genetic research. The original seed zone map developed in the 1960s (Figure 1a) is still valid and widely used in the nursery industry. Elevation is normally noted by 500-foot elevation bands within the seed zone. Elevation of origin is an important aspect of your seed source. Seed zones are often defined by geographic features such as mountain ranges, river drainages, and major valleys. Seed zones have been established throughout the Pacific Northwest region they identify areas where growing conditions are similar (Figures 1a–d). When ordering trees, geographic seed collection zones and elevation of origin are useful criteria to help match environmental conditions of the seed source with those of your planting area. Thus, it is important to plant seedlings grown from seed collected from a location where the environmental conditions closely match those in your area. Trees are genetically adapted to the environment in their area of origin. For example, on a coastal site with moist soils and shade from standing trees, consider planting a shade-tolerant species such as western hemlock. Tables 1a-d show considerations for selecting species for reforestation in each major region of Oregon, including the coast, Willamette Valley, western Cascades, and southwest and eastern Oregon. See the USDA Natural Resources Conservation Service soil survey at. Soil surveys are a good source of information on site productivity and soil-site-species relationships. Refer to species guides in soil surveys of your area.You can gather this information based on old stumps, historical records, or the knowledge of long-term, local residents. Try to identify tree species that naturally grew on or near your site before the first logging.If you are interested in planting a particular tree species, it is important to determine whether it is adapted to grow on your site, based on the site’s soils, climate, and other factors. Your county Extension forester can also answer additional questions that you may have. For information on short-term (15 years or less) reforestation goals such as fiber production or growing Christmas trees and other crops, please refer to publications focused on those subjects. For information on other topics essential to successful reforestation (for example, site preparation, proper planting technique, and follow-up vegetation control), see the list of Extension publications below. The focus of this publication is on selecting trees suitable for long-term health and productivity. Part 3 provides tips on finding and ordering seedlings.Part 2 discusses choosing nursery-grown stock with the right qualities to survive and show good initial growth.Part 1 describes selecting trees that are adapted for good, long-term growth under your local conditions. To help answer these questions, we have divided this publication into three parts:
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |