Q. What is your opinion of pines as landscape trees in
our desert climate? We have quite a few planted in our complex and our HOA is
discussing whether we should get rid of them or not because of their liability
and water use. Our landscaper tells us they have borers.
A. I’m a little suspicious of the borer diagnosis in pine
trees since it is rare for them. Have that diagnosis confirmed with a second or
third opinion. Aleppo Pine gets a blight that causes browning of needles and entire
branches.
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| Probably Aleppo Pine blight |
From a
distance this can look like borer damage. So far no one has discovered the cause
of Aleppo Pine Blight or how to control it but it’s thought to be related to
irrigation and not resulting from a pathogen or borers. Aleppo Pine Blight is
so common in the Las Vegas Valley that if a pine tree has brown branches, it is
an Aleppo Pine, not Mondell.
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| Eldarica or Mondell pine will get dieback in some branches as well but not as well documented as afghan (halapensis) pine blight |
My
opinion of pine trees used for landscaping in the desert is mixed. I don’t
think large pine trees should be planted here but I do understand their light shade
value once they have become established and mature. What makes me hesitate is
their removal I’m not sure if the shade they produce is worth the extensive
deep watering needed to keep them healthy and upright against strong winds. In some
lower elevations in the Valley, these large pine trees with extensive roots may
have tapped into shallow groundwater which could help with irrigation and
staying stable.
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| Japanese black pine has a distinctive look that attracts many landscape designers and architects. But in my opinion it is not a good choice for desert landscapes because of it doesn't seem to survive to maturity in our hot desert. |
Removing
existing, mature pine trees from the property will increase the resident’s electrical
costs used for cooling during the summer months. I would recommend that you
transition your landscape to smaller, desert adapted trees that shade the south
and west walls of your buildings and then possible pine removal. Once
established, their shade will substitute for the pine trees and help reduce
residential energy consumption.
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| Pine trees receiving adequate amounts of water develop a full canopy of needles and demonstrate good growth. But large mature trees need lots of water to stay healthy and deep irrigations to develop deep roots to withstand strong wind. |
It would
be far better to plant smaller pines such as pinion and Italian stone pine if a
pine tree is desired. Japanese black pine is sometimes recommended but look
around. Do you see any older Japanese black pine in the valley? Many have been
planted here. It doesn’t survive in the desert for any length of time so I
would discourage planting Japanese black pine here.
How do you tell if you have Aleppo or Mondell? Overall shape/density, bark, needles or cones? I assumed ours were Mondell.
ReplyDeleteWe have many on our (older) neighborhood and they do provide very good shade in the summer. A trade off to the almost year round clean up of needles. They are well established, I assumed the receive enough water by me as they look to be quite stable but I had not thought about them tapping into shallow groundwater.
When they are young they are very similar in many ways. They are both Christmas tree-like, they both have two needles joined together in a structure called a fascicle and the needles are about the same length. It is when they get older it can be easier to see the difference. Aleppo pine no longer develops a strong central leader...or Christmas tree shape while the Mondell does. After they get about 20 to 30 feet tall this central leader disappaears (most of the time) in halapensis (Aleppo) while the central leader stays in the center of the tree in Mondell (eldarica). But there can be alot of genetic variation in the trees and they can get confusing to tell the difference. Mondell pine needles are more "twisted" compared to halapensis in my opinion. That's why it is easier to look for aleppo pine blight sometimes. Sometimes they are easy to tell the difference and other times not so easy.
DeleteI live in the northwest and I have three that are big and one planted at the same time that has never done well. luck of the soil but I didn't plant that one. when we moved into this house 31 years ago the drillers well log said ground water at 27 feet, after five years of watering them I never watered them for 23 years. then three years ago I noticed that they looked water stressed so I watered each one for 7 days on a metered faucet which was 15,915 gallons making 2 cycles. I'm not sure if it's sustainable because It's more water than I am allotted. they shade the east and south sides of my house so I would hate to lose them.
DeleteMost pine trees have a tap root that grows pretty deep. The groundwater you experienced at 27 feet goes up and down. It hardly ever stays at 27 feet. That is called a “diurnal fluctuation” of groundwater or seasonal groundwater. The level of water goes up and down over the growing season. Usually, groundwater is deeper in the soil during the summer. But that is not always the case.
DeleteOver the thirty years you have been there you have probably seen lots of neighbors come. Most homeowners use groundwater from wells. This groundwater is lowered as more people “tap into it” with wells. This tapping into the groundwater by new residents lowers it. If this groundwater lowers too much, water is not available to your pine trees and water must be supplemented by irrigating them. If water that used to be available to them through their roots is no longer available then they die from a lack of water.
Aleppo, Japanese Black Pine and Italian Stone Pine have minds of their own when it comes to growing into interesting shapes. In Jan. 1975, we planted our first Aleppo pine, purchased as a 4'-tall Christmas tree in a 5-gallon bucket in December 1974. It is now over 50' tall with a trunk base circumference of about 11'. We had also planted Balm of Gilead Poplars because we love the ranch-look of cottonwoods, but eventually they contracted cytospora canker and had to be removed. Over time, we replaced them and added a total of 15 Allepos on the landscaped portion of our 2-1/2 acre property, along with 1 Italian stone pine, and the 3 types of local mesquites plus a couple of Chilean varieties to create a mesquite bosque. We also capitalized on the native acacia greggii and creosote brush already growing on the property. We decided against Mondales because their shapes are too formal for our more wilderness-look landscaping preferences. When the summer heat comes on, our pines often experience spotty dieback from heat stress; then we water a little more per water district regulations. We have no ground water, so irrigate with periodic fertilizer boosts. Our water bill runs around $350 during the hot months. We live on the far east side of Henderson, NV, on the rugged volcanic flank of the River Range, which usually runs 3-5 degrees warmer than the rest of the Las Vegas Valley. We have grass only in the root areas of the trees so both benefit and we can enjoy the meadow feel. And the wildlife loves the habitat we've created.
ReplyDelete