There are a lot of caterpillars on my oak tree, will they kill my tree?

They usually don’t kill your oak tree outright, but they can weaken the tree and make is easier for other problems to develop.

What should I do if caterpillar pests are eating my oak tree leaves?

The first step is to identify the problem correctly. We can help with that.

The next step is to decide on a course of action. Depending on the needs of the tree and how bad the infestation is, you have several choices.

What are the most important steps? 

Help your trees get healthy. Our oak trees are still recovering from the long term drought we experienced. Proper watering and nutritional needs are important. Oaks can be damaged by too much water, but not enough is a problem too. While they are adapted to long dry summers, the lack of rain in the winter for 5 years weakened the root systems of these trees. We may recommend deep, infrequent watering to help your trees recover. This is one of the most important things we can do.

Fix soil problems. Poor or compacted soil conditions, reduced rooting area and other soil issues all contribute to tree decline. Improving soil structure, de-compacting the soil, improving soil biology all help the tree get healthy again.

Protect your oaks for other invaders. There are many other insects and diseases that can attack your oak trees, especially if they are stressed from oakworm attacks. After we assess the trees, we may recommend proactive treatments to help protect your oaks while they recover.

Be proactive about caterpillars. If this is a reoccurring problem, the best time to treat is BEFORE the insects hatch. We can protect the trees with treatments made in the fall or winter that will reduce the population the following growing season. This is a very cost effective and safe treatment that stays inside the tree, so only insects that feed on the leaves are affected.

Treat today’s problem carefully. If there is a large population that is severely hurting your oak trees, we may recommend a canopy treatment with a biological control to slow down the problem fairly quickly.

If you are concerned about oakworm and want to schedule an inspection, fill out the form below.

Why are the leaves falling off my trees when they just leafed out? If you have sycamore trees, dogwood, Modesto ash or certain oak trees, they may be suffering from Anthracnose. This is a leaf disease affecting these tree types and a few others. The leaves are infected when they first come out, but the disease spreads and gets worse as the leaves mature. About the time your tree should be producing shade and capturing sunlight for energy production, the leaves die and drop off, creating a mess on the ground. On some trees, like the sycamore, the disease can affect the small twigs as well. Thus, you often see small and medium sizes twigs falling off these trees throughout the summer.  

Will this kill my tree? While anthracnose in and of itself does not kill a tree, it weakens the tree which allows other insects or diseases to attack the tree more readily. This happens because fewer leaves on the tree means it is not producing enough energy to make the auxins and other chemicals needed for tree defense. The tree also has to expend extra energy to put out new leaves, which often come later in the spring or in early summer.  

Why do my trees have this problem? Anthracnose likes cool moist weather, so a prolonged cool spring, with rain, fog or other moisture encourages the development of the disease. One good thing about this disease is that it is typically host specific, meaning that the anthracnose on your sycamore will not infect your maple trees. 

What can I do about it? The best way to discourage anthracnose is to make sure your trees are healthy and are pruned properly. Water properly – deep, infrequent watering throughout dry times, encourage proper growth with good nutrition and soil health (we usually recommend an organic based feeding that does both of these things), mulching to reduce water loss and tree stress. If your trees can benefit from treatment, it is best to start in the fall or early spring before the leaves come out. Sometimes multiple treatments are best, depending on the weather and the type of tree. 

If you are concerned about anthracnose and want to schedule an inspection, fill out the form below.

Why are the leaves on my tree looking whitish? 

During the spring, especially when it is cool and damp, your tree may be affected by powdery mildew. This is a fungus that punctures the leaves of trees to feed on the cells of the leaf. The fungus then grows on the surface of the leaf, making a white powdery look to the leaf surface. 

Will this hurt the tree? 

Most of the time, powdery mildew does little long-term damage to the tree. It often goes away on its own as the weather dries and warms. However, it indicates that there may be some other problems with your trees. Healthier trees that have been pruned properly often have much less powdery mildew. Trees planted in too much shade tend to be affected the most, so creating more sunlight in an area may reduce the problem. In a few cases, it can become so bad that the tree fails to thrive and needs to be removed. 

Will all my trees get this problem? 

No, many trees are very resistant to powdery mildew. Some trees that are more susceptible include apple, crabapple, crape myrtles, dogwood, flowering fruit trees, hawthorn, lilac, maple, oak, poplar and sycamore. 

When is the best time to protect these trees? 

Improving the health of the tree or pruning can occur as needed. When treatment is recommended, doing a preventative treatment in the fall or early spring is best. Control during the season is possible, but often requires several return visits to maintain good control. 

If you are concerned about powdery mildew and want to schedule an inspection, fill out the form below.

One of the most beautiful trees in the landscape is the birch tree. Soft foliage that flutters in the wind, smooth white or papery cream bark and beautiful fall colors make this tree a favorite for many people.

Unfortunately, it is also the favorite tree of a destructive insect called the bronze birch borer. This relatively small flying beetle has a deadly appetite for birch trees, burying through the outer bark to lay eggs inside the tree. The new larvae then eat the living tissue right below the bark, stopping the water and nutrients from getting to the top of the tree.

Dead tops on birch trees are the first visible sign, but protection of your trees should begin before then.

Your Arborwell arborist knows how to create a sound, cost effective plan to protect these trees in your landscape.

If you are concerned about the bronze birch borer and want to schedule an inspection, click the button at the top of the page.

Why Are Trees Important? 

It’s no secret that trees help the environment, but you may be surprised by all the benefits that planting and caring for your trees can provide.  Besides beautifying our properties and providing us shade in hot weather, trees have many environmental and economic benefits.  Trees save energy, reduce atmospheric carbon dioxide, and improve air quality. 

Properly-cared-for trees will increase property value.

Trees are a landscape’s most valuable asset.  Mature, well-maintained trees can add up to 20 percent more value to a real estate appraisal, as well as aesthetic curb appeal that draws positive attention to a property.  Conversely, deferred maintenance and poorly maintained trees can have the opposite effect on a property, potentially lowering its value up to 15 percent.  Trees that are not cared for properly can also create a large liability for the property owners and managers.  When trees have not been regularly inspected by an ISA Certified Arborist and kept appropriately pruned on a normal basis, there can be an increased potential for failure from heavy limbs.  If there is a poor root structure that has not been identified by an ISA Certified Arborist and cared for, then complete tree failure is liable to occur. 

Trees conserve building energy use.

Trees modify climate and conserve building energy use.  Trees and other vegetation on individual building sites may lower air temperatures 5˚F compared with sites without trees.  For individual buildings, strategically placed trees can increase energy efficiency in the summer and winter.  Because the summer sun is low in the east and west for several hours each day, solar angles must be considered; trees that face west-facing walls help keep buildings cool.  In the winter, allowing the sun to strike the southern side of a building can warm interior spaces. 

Trees improve air quality in their environment.

Air pollution is a serious health threat to many city dwellers, and often leads to the development of respiratory or heart diseases.  Urban forests absorb gaseous pollutants through leaf surfaces, as well has intercept pollutants such as dust, ash, pollen, and smoke.  Trees also release oxygen through photosynthesis.  In addition, they reduce energy use, which reduces emissions of pollutants from power plants. 

If tree biomass is properly recycled, it creates clean energy.

The way a tree’s biomass is recycled is very important to closing the carbon dioxide cycle.  Perhaps the greenest way to recycle tree waste is to send it to a biomass plant.  Numerous tree care companies in California send all of the tree biomass through a chipper to create wood-chips, and then those chips are transported to a biomass plant.  Once the chips arrive at the plant, they are dumped into large hoppers and fed into a furnace where they are burned.  The fire heats water in a boiler and the resulting steam is used to turn turbines and generators.  All of the power that is created is sent directly into the state’s power grid.  Burning biomass creates what experts call a “net gain of zero”. The small amount of emissions generated during biomass burning is offset by the amount of carbon dioxide that was absorbed by the biomass while it was growing.  Biomass power plants diligently work to ensure that emissions are kept to the absolute minimum.   

• Are there large, dead branches in the tree?
• Are there detached branches hanging in the tree?
• Does the tree have cavities or rotten wood along the trunk or in major branches?
• Are mushrooms present at the base of the tree?
• Are there cracks or splits in the trunk or where branches are attached?
• Have any branches fallen from the tree?
• Have adjacent trees fallen or died?
• Has the trunk developed a strong lean?
• Do many of the major branches arise from one point on the trunk?
• Have the roots been broken off, injured, or damaged by lowering the soil level, installing pavement, repairing sidewalks, or digging trenches?
• Has the leaves prematurely developed an unusual color or size?
• Have trees in adjacent wooded areas been removed?
• Has the tree been topped or otherwise heavily pruned?

Specific types of pruning may be necessary to maintain a mature tree in a healthy, safe, and attractive condition.

• Cleaning is the removal of dead, dying, diseased, weakly attached, and low vigor branches from the crown of a tree.
• Thinning is selective branch removal to improve structure and to increase light penetration and air movement throughout the crown. Proper thinning opens the foliage of a tree, reduces weight on heavy limbs, and helps retain the tree’s natural shape.
• Raising removes the lower branches from a tree to provide clearance for buildings, vehicles, pedestrians, and vistas.
• Reduction reduces the size of a tree. Reducing a tree’s height or spread is best accomplished by pruning back the leaders and branch terminals to secondary branches that are large enough to assume the terminal roles. Compared to topping, reduction helps maintain the form and structural integrity of the tree.

Why Plant Health Care, not Tree Health Care?

While trees are dominant ornamental features on your home or business landscape, they share this area with turfgrasses, shrubs, and other plants. All these plants are bedded in a common resource: the soil. The roots of trees, shrubs, turfgrass, and bedding plants intermingle and compete for water and nutrients. The roots of a single mature tree may extend well into your lawn or flower beds. Every treatment applied to the lawn (fertilizer and herbicide, for example) can impact the appearance and vitality of a tree. Conversely, treatments applied to a tree, such as pruning and fertilizing, can influence the appearance and vitality of the underlying turfgrass. The care of each plant in a landscape can affect the health of every plant in that landscape.