April 17, 2019 - 1:30pm -- smith.263

Be prepared . . . as it begins to turn hotter and probably drier in the coming weeks, we expect lots of trees and landscape plants throughout the county - especially needled trees and plants - to show the symptoms of decline and even death. Yes, unless they are planted in well drained soils, we're expecting that trees, in particular needled trees, will begin to collapse as soon as it gets hot and the soil begins to dry.

Unfortunately, there's little we can do at this point. The damage has been done over the past 14 months as we experienced the wettest year in history followed by above normal precipitation so far in 2019. And plants, especially needled plants, simply won't tolarate 'wet feet' for very long.

This is much the same as we expereienced during the early years of this decade. For a recap of what happend then, and what we expect is likely to happen again in the coming months, see below the article that was posted to our County Extension webpage back in July of 2015.

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Mother Nature is continuing her assault on area trees and landscape plants!

We continue to receive contact almost daily regarding the decline in appearance of many trees throughout the County. In fact, it's been happening for a few years now, and it’s also happening all over the Midwest. In a nutshell, here’s what's going on in nearly every case.

First it needs to be said that unless you have an ash tree, the issue is not likely originating from insects. Likewise, seldom has a disease been identified as the primary culprit. The problem is more than likely environmental.

More specifically, the abundant rainfall that’s hit the county this year has caused waterlogged soils that, when combined with the impact of multiple years of challenging, extreme weather, are taking a toll on the landscape! Like other plants, trees need a mixture of both air and water included with the soil they grow in. When abundant and frequent rainfall persists, the air pores in the soil are filled with water, and the roots begin to suffocate. Obviously, plants located in poorly drained soils suffer first, and the most.

Trees can tolerate lots of different kinds of stresses occasionally, but repeated extremes take a toll unless the tree is in a perfect soil environment. That ‘perfect’ soil environment includes well drained topsoil that is often characterized as a ‘native’ environment and not something man has created. Trees planted into a landscape near a home that was built within the last 30+/- are not always growing in ‘perfect’ soil conditions. As you might imagine, when bull dozers are used to smooth the soil's surface after a house has been constructed, seldom does it result in consistent amounts of top soil being replaced 8 inches deep throughout the entire landscape. When extremes in the weather and particularly precipitation begin to arrive, less than ideal soil conditions compound the problems created by that weather.

That being said, as we look back you might recall that the second half of 2010 was very hot and VERY dry.

2011 was the wettest year in 50+ years, to that point at least, with significantly above normal precipitation throughout nearly the entire year.

2012 was our driest year in 50+ years.

2013 was halfway normal, but the winter of 2013/14 was the coldest in decades and included a few days in January with nearly -20 degree temperatures. Last winter once again offered a week or more of extremely cold temperatures.

Following 4 to 5 years of the stress created by varying and extreme weather, the extraordinary amount of precipitation we’ve experienced thus far across the county this spring and summer is causing further decline in many trees. In particular, needled trees, oak and maples seem to be suffering the most. Many landscape plants are offering similar symptoms of decline. Should the abundant precipitation of the first half of this year be followed by a hot and dry second half of the year, it’s likely we’ll see further decline of trees and landscape plants. In fact, the full impact may not be realized until next spring.

The combination of stresses in recent years on the landscape has also made plants more susceptible to other health issues, in particular anthracnose leaf blight, leaf chlorosis (page 4 under that link), and phytophthora root rot. Unfortunately, there’s little that can be done to reverse the damage that’s been done to this point.

Those wanting to improve the appearance of deciduous trees showing the symptoms of decline that includes dead branches may cut those dead branches out, and then reshape the live portions of the tree. If we don’t experience more extraordinary weather for a few years, trees and landscape plants can recover and grow out again. If the rain completely stops and it becomes hot and dry, plants showing decline will likely need extra water in order to survive.

In the case of needled trees, if the needles are gone, the tree is likely dead and should be removed. If the intent is to replace the needled tree with a new one, keep in mind the factors that might have contributed to the decline of the original tree. Often times we plant needled trees very close together in order to create a wind break or visual screen. As those closely planted trees grow, some should be thinned out in order that the ones that remain have ample room for root growth.

Linked here is a fact sheet from Purdue that further describes the factors surrounding the decline and death of white pine trees.

Should drought like conditions develop later this summer, a look on page 3 of this Buckeye Yard and Garden Line post from 2012 about Drought Stressed Trees may also be helpful: http://bygl.osu.edu/content/drought-stressed-trees

- Stan Smith, OSU Extension PA, Fairfield County