Sunday, May 20, 2012

Hardwood Trees after the Drought

Some parts of Texas remain under an extreme drought, but here in Southeast Texas, we in The Woodlands Texas are only "dry". After several years of low rainfalls and extreme summer heat, our trees have been severely stressed. Under stress, the trees are vulnerable to disease. One such disease that takes advantage of this opportunity is a fungus called  Hypoxylon canker1. I had three trees alive with this disease for 14 years in my yard. In the 14th year, we had our severe 2011 drought, which killed all three trees. One hardwood, a Sweetgum, was killed from the disease 5 years ago. One killed in 2011 was a Red Oak (probably from Oak Wilt disease) and another was a Sweetgum. Now in 2012 another Sweetgum has died. All these hardwoods first lost top branches and decay set in at the top, gradually killing from the top down. After the trees die, the condition continues in the wood and behind the bark, revealing itself with obvious signs as in the photo below. Treating this condition is very difficult. Preventing the disease from continual advancement is accomplished by plenty of water. So extreme drought accompanied by extreme heat, creates just the right conditions to cause this fungal disease to thrive.
Note the black condition inside the bark 

Bark falling off the tree about a year later after the kill
The Texas Forestry Service predicts a loss between 100 million and 500 million trees in Texas from the 2011 drought2. That is a lot of trees! The impact from disease remains unknown. We will experience that this year and beyond! Certainly I am an example of the consequences of the drought on our hardwoods.

1 Hypoxylon Canker and Oaks, East Texas Gardening
2 Texas Forestry Service - Second phase of Drought Assessment

Thursday, January 5, 2012

Tree Planting Time Again

In The Woodlands, Texas, on the southern flank of the great East Texas forest, it is time to plant trees again. Arbor Day for 2012 will once again be celebrated in Rob Fleming Park in the Village of Creekside Park on Saturday, January 21 from 10 AM to 2 PM. There will be festivities with special events for children, as always.

In the spotlight will be free tree seedlings. I usually get about 12 seedlings each year and make an attempt to grow them. What I have discovered is that they are very susceptible to the summer heat. This past summer was the worse ever and my survival rate was only about 10%. That required a lot of frequent watering!

This year, one of my favorite trees is being offered - the River Birch. The bark of this tree gives it a rustic look in the yard, a signature no other local tree can boast about. This medium sized tree is ornamental and drought tolerant. If I plant nothing else, I would plant one of these. Another favorite of mine is also in the spotlight of seedlings this year - the White Oak.  This tree grows fast and huge, and produces an abundance of acorns to attract wildlife. A great shade tree! My squirrels love it.

Don't forget to plant pines also. Loblolly seedlings will also be distributed. Plant several together in the areas you really want them to be, because over the years, some will die off.  If four are planted one foot apart, one is likely to make it to maturity if you keep them all watered. Sun shading by nearby plants also helps in the summer sun. This pine will grow two feet per year, so in ten years you will have a substantial tree to enjoy.

One word of advice - always seek native drought resistant trees. If they grow here normally, many have likely survived significant droughts. This that grow in the East Texas forests naturally protect one another by utilizing the canopy to their advantage and do not normally require much water. But when placed next to concrete or into non-native soil, a tree requires extraordinary care.  Often the soil we plant them in is not very nutritionally rich enough to encourage aggressive growth, so we add nutrients. If the resultant soil is chemically altered, we face issues with survival, especially if those nutrients are heat generators. Decomposing materials are heat generators. Utilize the natural soil of the forest floor to the best of your ability. A pine will grow in about all the soils here while not all these trees will prosper in all soils.  I wold provide sufficient sand to the River Birch because you will find it flourishing near the creek naturally. Low areas with plenty of sand, like on Spring Creek provide an abundance of prospering trees, even in a drought such as we experienced this past summer. All of these trees love sandy loam soils.

Another word of advice - destroy any invasive trees, especially the Chinese Tallow. As the name implies, the tree comes from China, does not belong here and even kills trees around it by using its root system to deprive water from neighboring trees. It is against the law for a nursery to sell this tree. If you see it in a nursery, please report it. Please do not nurture these trees.

Other seedlings on this year's list are: (1) Two small early spring flowering trees - Dogwood and Redbud. My Redbud has grown so so slow, but remains alive and well after five years; maybe it will bloom for the first time this year! Two experimental Dogwoods did not survive that I planted last year. They were part of a nationwide study program. (2) Red Maple, Wax Myrtle.

Trees are fun and add diversity to our lives. In their adult lives, children can return to the place they planted trees when a child. We do the same as adults. I occasionally visit a home where I lived twenty-five years ago to see the Red Maples planted then in the front of each home. They make a beautiful canopy today on that street,which at the time was very bare. That was definitely a good idea to coordinate neighbors to line the street with a ten gallon tree. Though a tree may may take a long time to mature, it provides enjoyment for years afterwards, even to you returning to see the result of your work.

Hug a tree today and it will give you pleasure tomorrow.

Friday, October 28, 2011

A surprise in the Mitchell Preserve on Spring Creek

When taking a walk in George Mitchell Preserve off of Flintridge Dr in The Woodlands Texas, I ran across a small strand of trees which turned out to be Orange Trees. At first I thought the trees were a native lemon, but after asking friends, the species turns out to be Poncirus trifoliata, an Orange tree covered in huge thorns, adorning a lot of fruit, producing even through the drought. It withstood the very hard freezes we experienced the past two years.
Flying Dragon
The fruit is thick skinned, bitter and full of large seeds. It is a Japanese native tree that withstands the cold, heat and  drought. It was found growing prolifically and unattended in the sandy soils near the creek. It is invasive but appeared to be compatible with the surrounding vegetation.

Wild Orange trees typically have thorns. Grafted and cultured trees are often without thorns.

Sunday, September 11, 2011

Watering Trees in The Woodlands, especially during a drought

One stand of  trees die in the forest among others that survive

How to water trees in Southeast Texas applies to more than the Woodlands, but tests were run here, and I have had good enough success and failure to bring recommended methods forward and proclaim some best practices. I did this because of the generalities published elsewhere and the usual assumption that a tree stands by itself. I contend that life in our forests has some trees depending on others and all trees competing for moisture. Some trees are more resilient than others when it comes to no available water supply. This article is not only about watering a tree; it is about watering a forest. The photo above shows a stand of trees that died due to beetles and drought. Drought weakens the trees so that the beetle can attack it. Disease is often the result of drought. Healthy watered trees will have a 200% water content but a drought stressed tree will have half that.

This summer has been especially extreme through high heat, little rainfall and at times extremely low humidity. That combination causes fire danger AND threatens the lives of our trees, bushes and plants that normally can survive normal drought. During my experimentation this summer, I lost considerable turf in my yard trying to see where the threshold is on watering my trees. We have been under water conservation measures, confined to one inch of water per week, with two specific watering days allowed. Ours has been Thursdays and Sundays. You are allowed to hand water at other times, to keep your garden flowers from withering away and to care for special areas that may not survive the twice-a-week schedule. With these constraints, I worked out various ways to keep the trees alive.    

I have lost no large trees that were healthy before this summer dry season, but lost most of the trees planted on Arbor Day this year, half of the trees I planted last year and even a few trees planted three years ago on Arbor Day. I have planted and cared for trees in public areas as well and believe I lost some of those this summer. So why do I start with the trees I lost? Finding the balance between conservation of water and conservation of species is difficult, but my issue was mostly with trees already suffering from disease and past droughts, not necessarily my practices, except for one tree I never dreamed I would lose.  

Of utmost importance have been the 20+-year-old trees in my yard. These have been a priority. They are not replaceable without considerable expense. The 40-50 year old pines are huge. I would really hate to see them go! To cut one dead tree down of this size would cost nearly $1000.

So, here are the methods I have tested and proven to work. I can tell that these methods and strategies work by comparing with my neighbors who do not have such strategies. My neighbors had less loss than the surrounding green areas of forest, but they lost healthy big trees - mostly Oak and Pine. I did not.

Bucket Method

The bucket method  
I went to a local general store to purchase 12 5-gallon buckets. For me, I chose Home Depot because I happened to be there for some other reason and saw exactly what I wanted for sale. Spending about $30, I took them home and tested one with three small holes drilled in the bottom.
That turned out to be too much of an outlet, so I drilled one small hole in the bottom of each of the other buckets (about 1/8 in. drill bit) near one side of the bucket, not in the center. You need the flexibility of placing the hole near a small tree, so the hole was placed on the perimeter of the bottom, not the center. Water is pulled by gravity into the ground, so the area directly beneath the hole is place where the water will go.
Bucket configuration for one tree
     So I started using this method to water my Magnolia tree. Both of my neighbors lost their Magnolias. After I started this technique, mine became much healthier and now the larger one flourishes. The buckets are placed at the drip line of the tree. Note how uneven the configuration is above - that represents the outline of the limbs on that tree. Typically, an established tree will have roots branching out in the mirror image of the tree, under the ground about 4-6 inches. Many times we train our trees to root just one-two inches under the ground and even on the surface itself. That will dry out in three days under normal summer conditions. Where the tree can normally find water, that is where its roots go. Such a broad statement has it's exceptions as you might imagine. Hard clay soils tend to push roots to the surface and soft sandy soils lends itself to deeper rooting, but the rule still applies. I personally have both  situations in my yard. If watered frequently and shallow, the roots will depend on water being available all the time in shallow soil. The general recommendation by noted experts is to water every 10 days. I agree with that in times of severe drought. In times of exceptionally high temperatures, low humidity, and wind, smaller trees really need more frequent deep watering, as often as every 5 days. I normally do not water for two weeks or more if we get an inch of rain. This summer that has not happened one time! Before I left on vacation, just before the 100+ degree temps, low humidity and wind arrived from Tropical Storm Lee, I watered all my trees using the bucket method. Nine days later when I returned, there was no damage except my 15-foot Bald Cypress went brown like it does each late summer. It always comes back when the temperature is more moderate and the rain begins. By watering it when I returned, the browning immediately ceased and the tips of the branches remain green to this day.        
Using buckets for a random forest configuration of trees - canopy intersections

The bucket method is also good for forest areas, although a forest floor is best is it is generally with an inch of water soaked once every month, it will survive with the buckets every 10 days. Where the canopy of one tree intersects with another is a good place to place a bucket.

Remember that some trees are more  resistant to drought than others. My small 3-year-old Magnolia in the green area behind my home died from lack of water, because I did not water it before I left on vacation. It did not survive a 20-day fast; neither did four small pines in the same general location. Lesson? Water the trees thoroughly before you leave on vacation and have someone else do it if you are gone more than 10 days. If the situation is normal and there are accumulations of rain that exceeds 1/2 inch, my strategy is to not water the trees at all, except if the temp is 100+ and/or I have trees that have been in the ground less than 3 years. In those cases some of the trees get watered every 5 days. Sometimes, they have to be watered just like the flowers. Just keep an eye on them and the soil.
Measuring water delivered to the trees

 General area watering method
This method is always preferred but will not allow you to conform to watering regulations. You just program a watering system to deliver one inch of water at one time to your yard. That will get sufficient water to your tree roots every ten days. I have found that a cat foot container works well to measure the amount of water delivered.  Just dip a ruler in it and see where the water line come to the ruler marks. Using a uniform delivery sprinkler works well to get sufficient water to your trees. I have used an automatic shutoff timer for this method, and it works well. This is laborious but less so than the bucket method. The full inch must be delivered in one watering, you cannot deliver 1/2 in twice a week and get down far enough for many trees. There is a way to tell if you are getting sufficient dirt wet  in one watering. I test the ground with a long screwdriver. If it won't easily go into the ground 8 inches, it is not watered enough. But again, there are exceptions. If you have a heavy clay over your tree roots, You may not be able to get sufficient water that deep. Exceptional situations warrant exceptional processes. Just use common sense, but stay within the governing laws of the community.
Helical configuration of a soaker hose

Soaker Hose Method
I use this sometimes when I want a general area soaked down for a special tree. Lay out the hose beginning at the drip line and start a helical configuration towards the trunk. Never go to the trunk because a mature or aged tree is not effectively watered next to the trunk. Its roots stretch out where from where the leaves begin to the outer leaves vertically. You want the outer perimeter drip line of the tree to get the most water. This method can get expensive and cause you to use more water than permitted under neighborhood conservation measures. You can also measure delivery by placing the food can under the soaker hose.

So in general - I recommend the bucket method to conserve water and the general water method every 10-20 days if there are no constraints. I use the soaker hose for one special tree. All my pines get the buckets except for an occasional general thorough deep application by sprinkler or hose. This summer I applied of these general watering applications for the trees.

References - I have read many articles and seen several videos on this subject, as well as heard the experiences of others. I have no specific sources for you to access. These are my conclusions from the experience I have personally acquired, added to my own [past experiences and observations. Read related articles in the Commentary for additional insights and observations. If these methods do not work for you, I am sorry. I am only sharing what I have experienced and know works for me and my yard and has for over ten years.

Post publishing note: A question was asked me on email about the beetles. Apparently I have not identified the primary species of beetle that kill sour trees in Southeast Texas in prior articles. It is the IPS beetle, not the Southern Pine Beetle but we do have Southern Pine Beetles here and they do damage our trees.
Reference: University of Florida article on beetles, 1997 

Thursday, August 25, 2011

What is this tree?

This tree is truly a very special brilliant diamond in a massive and dark green forest. It stands out as a princess early every Spring to announce that the dance of life is about to commence. By necessity, it must attract pollinating agents such honey bees when the climate is dominantly cold. Yet is is abundant and thrives as one of the first trees to make this announcement alongside of its beauty competitor, a sapphire of the forest, the Redbud.

Saturday, August 6, 2011

Drought tolerance of trees in Southeast Texas

In 2011, we are experiencing the worse drought ever recorded in Texas. In The Woodlands, our forest is our most important asset that cannot be immediately replaced. We need to protect this asset.

Trees often reach deep into the soil to find moisture but some have shallower roots than others. The questions  "Are my trees dying?" and "How can I prevent my trees form dying?" have been raised by many of my readers and friends. Although I have written one other article on this subject, this year is different and we need to address the issue as it is. Here are the answers and some references to put you in the know. I have asked the same questions, so I share my findings and observations. Personally, I have trouble with pines, Magnolias and some hardwoods. I will list trees by name below and give you drought and water tolerance information. A very important thing to remember in the summer - there are trees which hibernate as a defensive mechanism. Unless you are sure the tree is dead, do not remove it until next Spring when it does not bud and produce leaves. If you know the name of the tree, you can use this as a  reference (and other internet sites) to see if it is hibernating, and then rid yourself of it if it is dead. Or you can consult with an arborist.

A tree will have a water content of 200% normally. In a bad drought, it will fall to 100% with the tree living. A large tree needs a lot of water to reach normalcy after it has declined to the severe drought level. At an extreme level, many will die for thirst. You can't allow a tree to reach that stage, because it likely will not recuperate.4

First, do water your trees!! Use a drip irrigation technique or an injection technique. I use a drip irrigation hose and a hand-held nozzle sprayer.  I also use a rotating sprayer if there are plants near the tree that also need to be watered. A friend of mine suggested going to a home supply store and getting a bunch of inexpensive buckets. Put a couple of holes in each one and fill with water to drip irrigate several trees at once. He uses this method for small fruit trees. You can use a triangular placement method. For trees I simply cannot live without, I lay  the hose around the tree in a helical configuration extended to the drip line.  Drip irrigate under low water pressure for one hour. I can see the water dripping, but it is not dripping fast. In 100 degree heat, without any rain, I will do this every 10 days to two weeks. For trees that can stand drought more such as pines, every three weeks. The Texas Forestry Service recommends watering each tree every 10 days 1-4 inches.1 The volume depends on the type of tree. If the roots are shallow and the ground is porous, 1-2 inches is about what I would use for the frequency I recommend.  Both the frequency and volume are dependent on the soil, species and weather. Always water in the evening to the early morning to match the hydration cycle of a tree. 4  If a tree has a low drought  tolerance, you need to pay close attention to it under heat stress and make sure you water the tree in advance of stressing it to the point of wilting. Watering is preventative medicine, not a cure. A nice little article I found searching via Google was in the Lufkin newspaper. 3

Here is a list of the trees I researched. I have most of them in my yard. I have adjusted some of the wording  to include local observations.
+ Bald Cypress: drought tolerant. Defense is to simply shed its leaves and hibernate. Small ones will eventually die if the dry period is for a long time. Tree is beautiful if kept watered. If no access to water, the tree will appear dead by leaves turning a dark brown.
+ Blackjack Oak - drought resistant - self defense is to hibernate and come back next Spring. Leaves turn brown and tree looks dead, but is not. Disease can kill the trees during this hibernation.
 + Bur Oak - very drought tolerant
+ Chinese Tallow: very drought resistant. Tree is hard to kill and invasive. These trees do not belong here. Please do not plant them. Instead, remove them from our ecosystems.
Crepe Myrtle - very drought tolerant. Excellent for cul-de-sac island.
+ Dogwood: low drought tolerance. Needs its water once a week.
+ Live Oak  - very drought tolerant. Also salt resistant. A Texas survivor. Tree likes its water and will grow much more rapidly when adequately watered.
Loblolly Pine: drought tolerant but highly intolerant under an attack by beetles and very vulnerable when small. Doesn't wilt, just dies. Hose configuration helical but from the trunk, not from the drip line.
Long Leaf Pine: very drought tolerant when large, vulnerable when small. Use same helical arrangement as Loblolly. Also highly vulnerable to insect damage and disease when under drought stress.
+ Magnolia: drought resistant - is susceptible to leaf browning and even death if no water at all
Mulberry: drought tolerant
+ Pecan: drought tolerant - needs water in fruit bearing months. Does best near and with water.
+ Redbud: drought tolerant, its leaves wilt easily but tree recovers at night
+ River Birch: drought tolerant - a strong survivor
+ Sawtooth Oak - drought resistant - will defoliate in self-defense against drought. Looks dead but is not.
Shumard Oak - very drought tolerant
Southern Red Oak: drought tolerant. Evidence indicates increased mortality in drought years
Sweetgum: low drought tolerance - watch closely for stress
Sycamore: drought tolerant
+ Texas Persimmon: extremely drought resistant. Survives when many others fail but also vulnerable to insect attacks.
Water Oak: low drought tolerance. Name says it all.
+ Wax Myrtle: drought resistant - definitely has its limits. Entire branches will die without water
White Oak:  very drought tolerant - may lose some limbs in drought
Willow Oak: drought tolerant. Does best where there is water.
+ Winged Elm: very drought resistant.Sheds leaves under duress
Yaupon: extremely drought resistant. Probably the most tolerant of all native trees. Lack of water affects berry production

+ There are many more trees to catalog. Generalizations are made such as "pecan" that is not necessarily true for all species. Breeding for drought tolerance is possible and in the case of food-bearing trees, is often the case. We are also likely to find exceptions to native species. I find articles through Google Search for the tree name and "drought", I can find the needed information on many trees. If you would like any additional name included, please let me know, and I will be glad to research and document the findings.

Sunday, January 23, 2011

Tree Planting Time in The Woodlands 2011


Arbor Day is always a fun day in The Woodlands Texas.  For the past few years, the festivities are held at Rob Fleming Park in the Village of Creekside Park. Lots of people in the area go to the event to obtain free tree seedlings. It is generally promoted by The Woodlands Development Company.  This year the following trees were distributed.

  1. Bald Cypress - native that loves water. Perfect for wet areas of the yard or on a body of water. These trees grow wild in or near ponds and marshy areas. They are well known to thrive in swamps. They will develop knobs from their root systems at the surface. Therefore it is not a good tree if you required grass in the shade under it. It grows slow. My 10 year old tree is about 15 feet tall growing in very good moist soil in the backyard in the sun. Trees on the pond grow slower for lack of nutrients. The tree sheds its leaves in the hot dry months of the summer and in the fall. They live for centuries. Perfect for a fishing hole on a pond. I have planted 100-200 of these trees since I moved here. 
  2. Flowering Dogwood - small early Spring native bloomer that thrives in partially shaded areas. It needs some sun but tends to flourish under the shade of larger trees in the forest. The tree turns a solid white before most trees even start leafing out in the Spring, typically in February. There are many in The Woodlands and in Southeast Texas. 
  3. Laurel Oak - one of our large natives oaks, known to tower about 60 feet high. It is a large (70 feet) fast growing tree with a relatively short life (50 yrs.). It is not cold resistant, freezing at about -3 degrees F; that is only 8 degrees under our known record low. 
  4. Loblolly Pine -  is not the native pine here but it is used by timber companies because it is more resistant to disease than the native Long Leaf Pine and a development company or lumber farm likes it because it grows very large (100 feet) faster than other varieties. Most of The Woodlands used to be a timber company. 
  5. Red Maple - large native tree (90 feet) having rich colors with of varying reds in the Fall. These are abundant among our forest trees and a favorite around homes. 
  6. Southern Crabapple - a well balanced native tree when planted alone in the sun and growing in moist soil. It is a medium size fast growing shade tree that has beautiful white flowers in the Spring. 
  7. Southern Wax Myrtle - small to medium sized bushy tree that is very useful to obstruct vision between homes or cut down on noise. It grows fast and is susceptible to varying boring insects which can cause weakness in the limbs. It is popular to provide a screen quickly and naturally. Some people let it grow wild. Others prefer it trimmed into shapes. 
  8. Wild Common Apple - small native variety that actually produces small apples. It grows to a height of about 30 feet.   





This year for entertainment there was a clown, face painters, musicians, recorded music, slides and a variety of children activities. For the adults, there were booths of information pertaining to nature, trees, recycling and even a recent trend - Zero Trash. Volunteers from the Woodlands Garden Club were distributing the seedlings. I planted half of my seedlings that afternoon. The volunteers were very generous, so I ended up with a lot of work to get them all in the ground.  There are five more Cypress trees on the pond to replace some of those lost in the drought. Reforestation occurs every year for me. Droughts have taken a heavy toll on seedlings for the last two years.