# Oaks and Acid Soil



## acipitor (Jan 25, 2007)

Many books I've read say that oak trees require acid soil, however, I've seen many here in SE Michigan growing in clay (alkaline) soil that seem to do just fine. The most common are the Bur, Northern Red, and Swamp White. I've planted quite a few other kinds of oaks this year (Black, Scarlet, Shingle, Willow, Chinkapin) and am anxious to see how they do. Pin Oaks I've seen with chlorosis are usually suffering from a lack of moisture, but Pin Oaks planted a few yards away that are well irrigated or in a low spot that gets more water have lush green leaves. Any thoughts or experience would be appreciated.


----------



## Kneejerk Bombas (Jan 25, 2007)

Chlorosis is not a normal indication of drought. In mature Oaks it usually indicates root damage, soil comapction, or lack of organic matter decaying on the root zone.
The one exception is the Pin Oak, Quercus palustris which become chlorotic when transplanted into alkiline soils. When you say Pin Oak, I wonder if you are talking about a Northern Pin Oak, Quercus ellipsoidalis, which actually do well in a wide range of soil pH.
Notice how rare it is to see a stand of chlorotic Oaks growing in a forest, even here in SE Wisconsin where we are on top of limestone bed rock that is often very shallow, even protruding through the soil surface. This is because the layer of organic matter decaying at the surface nuetralizes the pH, even thoiugh the soil always wants to revert back to the pH of the subsoil, there's a layer of soil at the surface that allows the tree to find what it needs.
Besides having a nice layer of organic matter for the trees, another sneaky way to lower pH is to include some evergreens into your plantings. Evergreen needles work well to lower pH, and by including them into your plantings you'll have a steady source of them dropping on the soil.


----------



## Thillmaine (Jan 25, 2007)

Dont know about out your way, but in Maine, tons of acid soils, and tons of red oaks. Down here in upstate NY, where the limestone belt starts, no red oaks, excpet up in the mountains where there is no limestone. Have seen other oaks that are doing okay here, aka Pin and Bur oak, but nothign like the beatutiful and majestic red.


----------



## RepublicOfTrees (Jan 25, 2007)

Chlorosis is a function of poor roots. That can be from a infinite number of factors like worng pH, too much water, too little water, recent transplant, competition from other veg (turfgrass), herbicide damage, living in a parking lot, etc. If you have two trees near each other and one is better irrigated it would follow that it may have a better root system and thus can better extract nutrients like Fe and Mn from the soil. Even trees like pin oaks that evolved to live in high organic, low pH soils can grow well, even thrive in higher pH soils if they have the appropriate roots to supprt them. 

When ever you have a chlorotic tree, see the canopy yellowing as a symptom of something going amiss with the roots and address that. You may need to use an iron supplement to nurse the tree along in the meantime while you do work to redevelop the damaged roots. There are good products out there if you just do a google for "chlorosis." Good luck!


----------



## acipitor (Jan 26, 2007)

Almost all of the Oaks I have (or will) be working with are planted on the city right-of-way between the sidewalk and the street, so putting evergreens there with them wouldn't be practical. All of the Pin Oaks I've seen around here are the regular one (palustris), which is the most common in cultivation. I was fortunate to find a Northern Pin Oak (ellipsoidalis) in a nursery last year. It's rare in cultivation, at least around here anyway. Black and Chinkapin Oaks, which are also supposed to tolerate alkaline soil, are just as hard to find. I had to purchase those mail order in smaller sizes. A local nursery ordered some Chinkapins for me for this spring. It appears that chlorosis problems on most Oaks may not show up until they get older and larger, although all the ones I've seen look fine. Of course, I can't be 100% certain of the soil they're planted in. I've seen Pin Oaks with chlorosis issues when they're 15 ft tall, especially when they are under stress.


----------



## windthrown (Jan 26, 2007)

*Chlorosis in oaks*

Here in the western US oaks grow well in both alkaline and acid soils. We have California Black Oaks and Oregon White Oaks here growing in rather acid soil. California black oaks do OK in alkaline soils in California too. In California where I lived the soils were mainly alkaline and tanbark, blue, and a dozen other oak types grow fine. Big issue in California varieties is that most are susceptible to oak root fungus, and any water in summer months will stress the oaks there. 

Chlorosis can commonly be a problem caused by either not enough nitrogen, or not enough iron. New leaves yellowing usually means lack of iron, old leaves yellowing usually means lack of nitrogen. Nitrogen is highly mobile in plants. Plants will sacrifice and move old leaf nitrogen to new growth in times of stress. Soil pH is an issue because iron in alkaline soils is fixed and not available to the plants. Use chelated iron to green up your plants in alkaline soils. Lack of nitorgen in plants growing in acid soils can also be casued by lack of phosphate. Phosphate is less available to plant roots in acid soils, so in that case add triple phosphate as well as nitrogen.


----------

