A group of Linn County woodland owners on their annual picnic outing, stood in the shade of a 25 year old Douglas-fir plantation on McCully Mountain on a warm afternoon two weeks ago, as Linda Butts talked about the history and growth of the stand. Planted at 440 T/A, pruned to 8 feet and thinned with a processor three years ago to 170 T/A, it was easy to move around, see the condition of the leave trees, and how they were growing. The group talked about the thinning, small wood markets (Linda sold thinning as pulp or chip & saw), and of course there was some discussion (unresolved) about whether or not they had taken quite enough trees or not. But all agreed the stand was looking pretty darn good.
We also talked a fair bit about getting the stand started 25 yrs ago. Joining Linda in the discussion were Mike Barsotti and Rod Bardell, retired ODF Service Foresters who had worked with her and other private family forestland owners much of their careers. What was fun for me was listening to their recollections not just about that particular planting, but also about how much was being learned about planting and establishment in the 70’s and 80’s. It is always interesting to hear from some of the pioneers. Continue reading →
By David Shaw, OSU Extension Forest Health Specialist
Insects of Oregon white oak are causing some damage this summer, and you may be seeing trees that look completely brown or have scattered dead branches (distinct brown foliage clumps all through the crown). There are two different issues that have emerged around the Valley this summer: whole tree defoliation/leaf eating by the western oak looper (Lamdina fiscellaria somniaria); and scattered branch death caused by the combination of a twig gall wasp (Bassettia ligni) and the western grey squirrel.
The western oak looper (a type of inchworm) is a flashy defoliator that is a native in the Willamette Valley. The caterpillars are messy feeders, hang by silken threads, and leave browned mostly consumed leaves all over the tree, giving the tree the appearance of being dead. But the oak trees usually come back the next year. Historically, the outbreaks have been of short duration in any single area (typically one or two years) and the oak trees rarely suffer long term damage even though the defoliation may be spectacular. However, when conifers such as Douglas-fir are intermingled with affected oaks, they can also be defoliated in an outbreak and impacts to the Douglas-fir may be more severe. Continue reading →
Fire Season is now or soon will be in effect in much of the Tree Topics reading area, as declared by the State Forester according to regional fire conditions. So I got online to see what’s been declared. I went over to the ODF Wildfire website and clicked on Forest Restrictions and Closures section. There you can find links to an overview of the Industrial Fire Precaution Level (IFPL), closures and other information about fire regulations and restrictions. Continue reading →
Do you struggle with ways to engage your child, grandchild, or a young scientist friend with our local forest lands? I would like to suggest a new book, Ellie’s Log, to nurture your young scientist, and to help you both explore the mysteries in our collective backyard of Oregon’s forests. Ellie’s Log is part fictional story, part forest ecology lesson, and part field journal all set in a mature Douglas-fir forest in Oregon. Continue reading →
Last week, we kicked off our Master Woodland Manager training in northwest Oregon. Over the next six months the class will explore many aspects of small woodlands management and the trainees will come away with a better understanding of their own lands as well as a foundation from which to assist others.
We started out with a field tour where we investigated the environmental factors that influence forest growth on a given site. In particular, we wanted to see how variations in climate, topography and soil shape species composition, forest productivity, and management opportunities.
We went to five different sites, at various elevations and topographic positions from the uplands to the Valley floor. Despite the sites all being within a four-mile radius, we saw striking differences in the vegetation. The uppermost site supported a fast-growing stand of Douglas-fir and red alder. Further along, we came upon a rocky, south-facing site dominated by madrone and some not-as-fast-growing Douglas-fir; but this was just a few hundred yards from another site where the madrone were gone. Calculating the site index revealed that the Douglas-fir here were growing faster.
As we traveled down the watershed, the steep slopes along an upland creek supported alder and western redcedar. But on the flats further down the watershed, at our last stop on the Valley floor, the dominant species were Oregon white oak, Oregon ash, and valley ponderosa pine; the Douglas-fir at this last stop looked like they had caught a bad case of the crud.
Prior to the field tour, we spent some time learning how to find information about soils. The Web Soil Survey is a really handy tool for identifying soil types and learning about their properties. Using the Web Soil Survey, we mapped out our field sites and found some possible clues to our site differences. According to our soils map, the madrone were growing on a gravelly Saum soil, whereas the taller firs down the road were on the more productive Jory soil.
A recently formed gully at the latter site gave us the opportunity to see the soil profile which revealed a deep silty clay loam.
Recently I’ve discovered SoilWeb, which has become one of my favorite natural resources-related mobile apps, available for both the iPhone and Android. Using your phone’s GPS capability, SoilWeb accesses the soil data from the Web Soil Survey for the soil right underneath your feet. That is, assuming A) that you are in a place where you can get a phone signal and B) that the soil maps accurately reflect the soil on your site. As we learned on our field trip, soil types as mapped often contain unmapped pockets of other soils. The SoilWeb app doesn’t give you everything you can find on Web Soil Survey, but you can quickly ascertain the soil texture as well as the expected depth, drainage, and other important features.
The takeaway from our tour was that what’s growing on your forest can be a clue to your site’s underlying environmental influences, and vice-versa. The growing number of applications such as SoilWeb makes it easier to be a site “sleuth”, finding those clues and piecing together the puzzle.
The phone has been ringing off the hook lately with calls from people describing sick and dying Douglas-fir and other conifer trees. The trees are of a wide range of ages and in many environments and settings, although most calls have been coming from within the valley margin and have to do with young trees.
So far, the answer is generally: “It is drought stress”. Huh, in May? Well it has been a dry winter and spring, … but that is not the issue.
My best explanation is that we had a pretty hard end of summer last year. Remember that? NO rain until mid-October then, Boom, it was winter. By then, many trees had started running out of water, killing tops or branches, and leaving leaders and branches susceptible to attack by various opportunistic pests.
We started seeing a few classic signs of drought stress (tops dying and branches “flaring out”) at the very end of the season last year, but late enough that many did not have time to show up before the weather turned. Injuries had occurred, so it was just a matter of time before they expressed themselves, which is happening now. The recent hot weather seems to have made it more sudden and dramatic.
It is important to keep in mind that the Willamette Valley can be a challenging climate for trees. Many of our soils in the valley are poorly drained, which is hard on most of our conifers, and other soils are fairly shallow and cannot hold much water. Also our summers are hotter and drier than in the mountains. Heat and drought stress can kill trees outright, or more often just put the trees under stress, which can then lead to pest problems (as explained in the two publications above). From what I am seeing and hearing, the major cause of the problem now seems to be drought stress. Insect or diseases which able to take advantage of a stressed tree’s condition may sometimes be involved, but they are generally not the cause of the problems.
Finally, weather can be more stressful when trees are overcrowded, so thinning stands to keep trees vigorous with adequate growing space may be helpful in the long term. Right now, we just have to wait it out, and hope we get some serious rain this year, or we will see this problem intensify.
“We’ve never left much on the ground in the way of dead wood…not during logging, but wind damaged, etc. Our thought has always been that these rotting logs increase the insects in the forest, both good and bad. Is this a valid concern and if so, where is the balance between bugs and wildlife?”
He raises a point worth exploring. While calling an insect “good” or “bad” is a matter of perspective, for the purposes of this discussion let’s assume that “bad” insects are those that cause economic or environmental damage, and “good” insects are those that don’t. The vast majority of insects that inhabit western Oregon forests fall into the “good” category…with a few notable exceptions.
One of these “bad” bugs that the e-mailer might have in mind is the Douglas-fir beetle. This time of year, the adult beetles are flying around in search of Douglas-fir trees where they lay their eggs underneath the bark. Their favorite targets are large diameter, freshly downed logs—or standing trees that are weakened from another cause (root disease, soil compaction, etc.). Through the summer and winter, the eggs hatch and the larvae grow as they tunnel around under the bark (this activity is what kills the tree). The following spring, they have become adult beetles, and they fly away in search of new homes. If they can’t find another weak tree or fresh log, they will go after a healthy tree.
Healthy trees can withstand a low-level Douglas-fir beetle attack, and in normal circumstances there are rarely enough beetles around to cause concern. The problem arises when the beetle population builds up and lots of them infest a healthy tree at once. When does that happen? In situations where there is a lot of freshly downed or damaged wood on the ground for them to target initially – like after a winter windstorm.
Here’s a true story for illustration.
In fall 2009, a landowner in the Coast Range was hit hard by beetle kill to his otherwise healthy, 100+ year old forest. Why? Here’s how we think this may have played out.
The stand is adjacent to a sawmill.
The big windstorm of December 2007 created lots of blowdown along the coast, though this particular stand was too far inland to be damaged.
Some of the coastal blowdown was not salvaged until summer 2008…too late, because Douglas-fir beetles had already found them during the spring.
The salvaged logs were brought to the mill, along with the beetle larvae living under the bark.
Then, in late 2008 the recession hit and the mill curtailed operations. The logs sat in the deck…and the beetles matured.
In spring 2009, they emerged and flew off to the neighboring stand, where they attacked the healthy, mature trees.
It was a sad situation, especially since the landowner had to cut more trees to avert further beetle damage, and in a poor market.
So, back to the e-mailer’s question: does retaining snags and downed wood for wildlife create a forest health risk? The take-home messages are these:
Most insects are not forest health risks.
In western Oregon, the Douglas-fir beetle (the “baddest” dead wood-inhabiting insect) only thrives in FRESHLY dead or downed trees. Once the snag or downed wood has been dead for more than a year, it is no longer a target. Instead, it will become inhabited by the dozens of “good” bugs that feed wildlife.
There needs a LOT of this fresh down wood to pose a forest health risk – like after a storm. According to Oregon Department of Forestry, a good rule of thumb is that fewer than 3 FRESH down logs/acre does not present a hazard.
After a windstorm or other stand-damaging event, yes, prompt salvage is important in order to prevent a beetle infestation. But, when scattered trees gradually die in a stand from other causes, it is hard to imagine when this would create a risky situation with respect to bark beetles. And during harvest activities, you can be strategic about how much dead wood is left behind, and in what conditions.
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I recently was at a conference on “Wildlife in Managed Forests” sponsored by the Oregon Society of American Foresters and the Oregon chapter of The Wildlife Society. Speakers discussed current research on wildlife damage and wildlife habitat enhancement projects across western Oregon and Washington. There was far too much interesting stuff for this short article, so in this post I will focus on one recurring theme of the meeting. It’s one of the easiest and most effective ways to maintain a wildlife-friendly forest: retaining dead wood as snags (standing dead trees) or downed wood (on the ground). I’ll return to some other topics later.
Nearly 100 species of animals in Oregon (mostly birds) use snags. First, birds such as woodpeckers forage on insects living in these trees and then excavate cavities in them for nesting. Later, these cavities are used by other bird and mammals for nesting and shelter. Raptors such as hawks may also use snags as perches, from which they can prey on voles or other mammals that might damage seedlings.
With snags, the rule of thumb is “bigger is better” – smaller diameter snags will only be used by smaller animals and do not last as long. So if scattered trees die on your property, consider leaving them for wildlife, keeping safety in mind. Snags can also be created artificially during harvest. Mechanical harvesters can top trees up to 20 feet or so, and so can create a snag out of a tree with a defect down low but a merchantable top. The second best option, if you cannot safely cut the tree up high, is to fell the tree and leave the defective portion in the woods where wildlife will use it. Now it has become “downed wood.”
Just a few days after the workshop, I was out visiting with a landowner near Rainier. A small harvest had just been completed, and the logger had left a big, defective log alongside the unit (shown in photo below). The owner wondered, could it have been sold as a pulp log? Should she see if someone wanted it for firewood? I suggested that the log was already providing value, and probably more than what might have ended up in her wallet from these potential uses. Downed wood is used for cover, travel corridors, breeding spaces, and are especially important for amphibians such as newts.
The naturally regenerated alder in the background had come in after a harvest that had left little to no wood on the ground. The foreground will soon be planted back to conifers, which will take decades to reach a size that will provide a new source of snags or downed wood. By carrying over some downed wood like the log in the photo from one forest generation to the next, you can ensure some continuity of these wildlife-friendly habitat elements. Consider not disturbing down logs that are already in your forest – they are playing an important role, and besides, your equipment may take a beating if you try to move them or run them over!
Have you created or left snags or downed wood on your property? Do you have evidence of wildlife using these structures? I would like to create a photo gallery. Send me a photo of dead wood in your forest with a description of how it came to be or who you think is using it. If I get enough responses, I’ll share them all in a future article.
I recently got a call from a guy selling some woodland property in the Coast Range. A prospective buyer recently told him that he had Swiss needle cast (SNC) and so was not interested in buying the property. It is not hard to find the disease in western Oregon. It is a native disease of Douglas-fir and is wide spread from the coast into the Cascades. But this fellow was calling for some guidance about how to respond to this concern. Was it reasonable? How can he gauge its impact on his young forest stand?
He already knows how to recognize SNC when he sees it: from a distance it makes a tree look paleand sparse. This is because the fungus is developing in the needles, gradually clogging the stomates, which is where the leaf exchanges water vapor, carbon dioxide and oxygen. Up close with a hand lens you can look on the underside of a diseased needle and see tiny black dots in neat rows where healthy white dots (the stomates) should be visible. In some places or during seasons when the disease is severe, this causes many needles to turn yellow, and eventually to drop (to cast), giving the recognizable symptoms. If enough stomates get plugged, and or enough needles are cast the disease begins to affect photosynthesis, and possibly growth, the crux of the caller’s question.
“The key to understanding the impacts from Swiss needle cast,” says Dave Shaw, OSU Extension Forest Health Specialist and Director of the SNC Cooperative, “is whether the needle retention on the tree is good or not. If the tree is retaining around 3 years of needles, then growth should be close to normal. The impacts occur when needle retention is below three years, and especially when it drops to 2 years or less.”
So, the question for the caller is: “What is your average needle retention in these stands?” If near 3 years, he can tell folks that yeah, the disease is around but the stand is doing ok.
To count needle retention, use binoculars and cruise the stand, taking the needle retention from the mid crown, south side of tree, and not the apical stem, but the 4-yr and older side branches. There is a good illustration of branching and needle cohorts on page 3 of Swiss needle cast of Douglas-fir in Oregon. This time of year is good. Even if the stand is discolored a little, needle retention is the key factor.
More information about SNC can be found on the SNC Cooperative website, which has aerial survey data, research findings and even a Stand Assessment Tool that provides a more quantitative approach to assessing impacts on growth.
Feel like spring to you? It did to me earlier this week on a sunny walk in the woods. I spotted new leaves on many of our native shrubs, including Indian plum, huckleberry, elderberry, red flowering currant and salmonberry. These caught my attention particularly because I’ve just started dipping a toe in a new project – tracking phenology of a couple of our forest plant species through the National Phenology Network’s Nature’s Notebook.
Phenology? It is the timing of seasonal events in the life of a plant or animal. For plants, important phenological events include bud break, flowering, fruiting, or leaf drop. For animals, they are things like migration or egg hatch. These events have a predictable annual sequence that is tied to weather and climate patterns and ensures the survival of the species. Plants have adapted to their local environments such that they do not leaf out if they are likely to be damaged by frost; nectar-feeding insects’ life cycles are tied to the plants that they feed on.
Why phenology? Other than appreciating those first signs of spring, there are many practical ways that phenology ties into forest function and forest management. Here are a few examples that come to mind for me. Do you use herbicides around newly planted trees to control brush? Then you may monitor when your seedlings break and set buds so as not to chemically damage them. Do you rely on non-chemical methods of weed control such as mowing? Then you pay attention to when your target plants flower and set seed so that you can time your actions accordingly for best results. And, the timing of these events varies across the range of a particular plant species. That is why we have seed zones to ensure that when it comes to reforestation we “plant local”.
In the face of climate change, scientists are paying particular attention to phenology and interactions among species. For example, if due to an earlier spring, a nectar-feeding bird species begins to migrate earlier, but the phenology of a plant species in its summer range does not change, then the bird may not have a food source and the plant may not get pollinated.
Like tracking precipitation through CoCoRaHS, which I wrote about a few months back, tracking phenology is easy to do in your own woodland or even your own backyard. You choose a species from the many that are in the Nature’s Notebook database. You create an online account. Then you start observing your chosen species. This is another example of citizen science, where collectively the power of thousands of individuals gathering data can inform scientists and contribute to their research.
Oh yes…to the app. Nature’s Notebook has an App for Android and iPhone so that you can submit your observations right on your smartphone. How convenient! No need to remember to log into your computer when you get home. Just bring your phone out with you to the woods. I am using the app on my iPhone. It’s pretty basic, but it gets the job done.
Extension programs across the country are starting to adopt Nature’s Notebook with their volunteers. I’ve given some thought to this; hence my toe-dipping experiment. If you are a phenology tracker or become inspired to be one through this post, I’d love to hear from you. Comment on the blog, or send me an email.