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Serving small woodland owners and managers in the Willamette Valley and northwest Oregon
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Potential drawbacks of Young Stand Thinning

Wed, 02/07/2018 - 3:21pm

Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension agent, Benton, Linn and Polk Counties.

We have been dedicating a fair amount of screen space and class time lately to the idea that many family forest landowners would benefit from thinning their young stands. We explored the reasons to consider young stand thinning (YST) as well as some approaches in a series of posts on YST .  YST is consistent with the situation and goals of many family forest landowners, which often include growing older and more diverse forests.

That said, like many other well-grounded activities, YST is not without some potential drawbacks.

Few of them are significant enough to justify not thinning at all, but each requires some thought and consideration to avoid unintended consequences. We present some of those potential drawbacks that you need to consider when planning a YST, along with some links to other information, below.

Weeds. Yes, blackberries and other weeds can make YST difficult, and may slow the growth of your trees, but do not change the need for YST if you find that you have more trees per acre (tpa) than your desired target.  YST is  probably a better justification for keeping ahead the weeds, than weeds are a justification for delaying or not doing YST.

Sunscald, yes your trees can be burned if young tender bark is abruptly exposed to the sun and gets too hot.  We see it particularly on warm, dry, south facing sites, and it is more commonly seen because of pruning than thinning.  If your site meets that description, it might be wise to thin and prune separately.  Consider modifying the pruning operation (do smaller lifts, leave a SW facing branch or two in exposed places like south facing road sides, don’t prune those areas in late summer).

Insects and diseases are the most significant concerns related to YST.  There is the potential to create a bug problem while trying to avoid a density related stress problems.  The outcome depends on the amount, timing and handling of the slash produced.  The cause for concern varies by tree species.

Valley ponderosa pine.  We have written about problems with slash and the ips beetle before and also directed people or one or another excellent ODF bulletin about ips and also about slash management. These destructive bark beetles thrive on stress and also disturbances that produce debris they use to multiply.  Creating lots of slash in a thinning operation can easily lead to an ips outbreak, and certainly represents the biggest single challenge to managing pine.

Douglas-fir. Black stain root rot is an increasing problem in some areas in western Oregon.  It is caused by a fungus, but it is carried

Black stain signs at root crown.  Photo by William Jacobi, Colorado State University, Bugwood.org

by insects that are keyed-in on stress and disturbance (just like the ips).  Local outbreaks in young plantations may be associated with nearby disturbances such as harvests, road construction or brushing.  It can also be associated with YST.  Where other local disturbances or presence of disease cause concern, the most significant management recommendation is to avoid attracting and feeding the insect vectors by thinning in summer, after the insects’ breeding season.  Look for more about this disease in future blogs/articles.

Swiss Needle Cast is present throughout western Oregon, but it is most significant along the coast where it must be considered as part of every management decision. Potential implications of SNC to young stand thinning include retaining alternate species, and selecting among Douglas-fir based on needle retention.

Young stand thinning is an important woodland management practice that can help you keep your woodland vigorous and resilient to drought and other stress. A little caution can help it deliver on that promise.

The post Potential drawbacks of Young Stand Thinning appeared first on TreeTopics.

Categories: OSU Extension Blogs

Bringing nature to the city

Mon, 02/05/2018 - 2:28pm

By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington & Yamhill Counties

Taking a walk through my NE Portland neighborhood recently, I came across something new in our local park. Portland Parks and Recreation is renovating an underutilized section of Alberta Park as a “Nature Patch”.

Alberta Park was part of a Homestead Act land claim over 150 years ago, and became a park in 1917. (Check out a local historian’s writeup for the details.) So over 150 years of human use, the land is far from the forest that once grew there. The Nature Patch could be thought of as a re-engineering project.

Alberta Park in 1929 and 2018. If you look closely, you’ll see the lamp posts are still there. 1929 Photo courtesy City of Portland archives.

Like many of Portland’s parks, Alberta Park is dominated by towering Douglas-fir trees which cast shade on the playgrounds, lawns, off-leash areas, and other park amenities. But walking on the new gravel path through the one-acre Nature Patch, I saw how elements of a functioning, diverse forest are being reintroduced. Dead trees have been felled and left in place as downed wood, or cut to a safe height to remain as a snag. Understory planting is in progress, with pollinator-friendly plants like Oregon-grape, ninebark, and snowberry, as well as ferns and even herbaceous forest plants like oxalis. When the understory fills in, I think it will be quite lovely and a vast improvement over the muddy, sparse grass that had a hard time growing under the Douglas-firs’ shade.

 

A dead or declining tree was turned into a snag, safely away from the pedestrian path.

 

Oregon-grape is one of the earliest blooming woodland plants. It needs some sun to produce flowers.

Why am I writing about an urban park on a blog for small woodland owners? Well, I think there are some parallel lessons that woodland owners can draw from the Alberta Nature Patch.

  1. The designers did an excellent job of working with their existing urban forest landscape to introduce structural and biological diversity. Indeed, many of the elements we wrote about in previous blog posts are on display here: snags, downed woody debris, and understory shrubs and forbs.
  2. It also demonstrates a concept we discussed in a previous case study: that not all acres of your woodland (or park) need to serve all of your management objectives at the same time. You can compartmentalize if you need to. An off-leash area, a playground, and a ball field – all areas that are critical to the recreation mission of the site – border the Nature Patch at Alberta Park. You can have some areas that you manage more intensively for timber, and others, maybe those that are inherently less productive, for habitat.

    The Nature Patch in the foreground with the playground behind it

  3. This project illustrates that no area is too small or too urban for wildlife to benefit. Particularly, pollinators such as bees, who need our help. We’re still learning about how bees and other pollinators use forests. But they frequent open, sunny areas where flowering plants flourish. These might be along your roadsides, forest edges, or in a recently logged area. A new publication from OFRI outlines some steps woodland owners can take to make forests pollinator-friendly.
  4. Perhaps the greatest value of the Nature Patch lies in public exposure. Living on a small woodland, it can be easy to forget that many people in cities, especially those who don’t have a car, don’t have easy access to nature. For some people who have always lived in an urban environment, forests might even feel unfamiliar or intimidating. Bringing a bit of native forest to the city park exposes park users to a setting that woodland owners take for granted. I like to think that exposure gives way to appreciation. We in the forest sector need ALL Oregonians to appreciate forests.
  5. Like Alberta Park, the land that many small woodland owners care for often has seen many previous uses. If your woodland was once a farm, pasture, or even an industrially managed forest, many elements of a native forest are missing. Reintroducing diversity to a forest requires intention. But if it can be done in an urban park, surely it can be done on a small woodland. Where is the “Nature Patch” on your place?

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Categories: OSU Extension Blogs