Austrian Pine Discoloration - Ask Extension
Do you know what could be causing one of my Austrian Pines to discolor?
Knowledgebase
Austrian Pine Discoloration #833034
Asked May 31, 2023, 6:12 PM EDT
Do you know what could be causing one of my Austrian Pines to discolor?
El Paso County Colorado
Expert Response
Hello Michael,
Thank you for contacting Ask Extension. You have a concern about one of your Austrian pines being discolored. I see browning of the inner needles near the bottom of your tree which looks like the normal needle shedding process that pines experience during the fall. The shedding begins near the top of the tree and moves downward. Perhaps the shedding needles near the bottom of the tree have not dropped yet. Austrian pines shed their needles every 4 years. I see new buds on the tips of the browning branches that look the same size as those on the green branches. Underneath the discolored tree I see lots of shed needles. Your multiple Austrian pines may shedding needles different years. If the tree was browning from the tips that could indicate a problem. I am sending you several articles about the pine needle shedding process.
https://planttalk.colostate.edu/topics/weeds-cultural-problems/2123-needle-browning-evergreens/
https://csfs.colostate.edu/2017/09/07/dying-off-color-pine-needles-normal-autumn/
https://extension.usu.edu/forestry/trees-cities-towns/tree-care/pine-losing-needles
https://byf.unl.edu/natural-needle-drop
https://extension.usu.edu/forestry/trees-cities-towns/tree-care/pine-losing-needles
If you feel that this is not what is happening to your tree, please send detailed pictures of the brown and green needles and affected branches. Is the tree next to the browning tree the same species, it is hard to see in the picture? This tree is a darker shade of green with larger candles.
Thank you.
Thank you for contacting Ask Extension. You have a concern about one of your Austrian pines being discolored. I see browning of the inner needles near the bottom of your tree which looks like the normal needle shedding process that pines experience during the fall. The shedding begins near the top of the tree and moves downward. Perhaps the shedding needles near the bottom of the tree have not dropped yet. Austrian pines shed their needles every 4 years. I see new buds on the tips of the browning branches that look the same size as those on the green branches. Underneath the discolored tree I see lots of shed needles. Your multiple Austrian pines may shedding needles different years. If the tree was browning from the tips that could indicate a problem. I am sending you several articles about the pine needle shedding process.
https://planttalk.colostate.edu/topics/weeds-cultural-problems/2123-needle-browning-evergreens/
https://csfs.colostate.edu/2017/09/07/dying-off-color-pine-needles-normal-autumn/
https://extension.usu.edu/forestry/trees-cities-towns/tree-care/pine-losing-needles
https://byf.unl.edu/natural-needle-drop
https://extension.usu.edu/forestry/trees-cities-towns/tree-care/pine-losing-needles
If you feel that this is not what is happening to your tree, please send detailed pictures of the brown and green needles and affected branches. Is the tree next to the browning tree the same species, it is hard to see in the picture? This tree is a darker shade of green with larger candles.
Thank you.
Hi Barbara,
Thank you very much for your response. I don't believe it is shedding as it already shed not long ago along with the same tree next to it. Plus the identical tree 10 feet away is doing great. Both trees have always done great, but this spring I recently noticed the discoloration and budding suddenly stopped. Do you think it could be wind burn, too much water from rain that has caused root rot, or something else? I attached more pictures.
Thank you,
Hello Michael,
Thank you for your additional pictures and information, very informative. You describe the declining tree as being discolored with budding suddenly stopped. Would you describe the color as turning grey green? It looks like the tree is producing new cones. The whitish area around the new cones looks to be a normal process of cone development. The needles on the tree look healthy.
https://www.waterwiseplants.org/find-a-plant/austrian-pine/
I have some questions to ask you to help narrow down the cause of your tree's decline. I have noticed that the area around the trees is surrounded by wood and rock mulch plus sidewalks. I see no weeds in the area. Is there landscape fabric under the mulch? Has any construction occurred in the area that could damage the trees roots. Do the trees receive supplemental irrigation or have any fertilizers, pesticides or herbicides been used in the area. Austrian pines require a moderate amount of irrigation.
Here is some information from OSU about abiotic damage to Christmas trees. Different types of damage can be selected.
https://pubs.extension.oregonstate.edu/pnw659/fertilizer-burn
I am sending Environmental Disorders of Woody Plants, please note the drought section. I do not see drought symptoms on your pine.
https://extension.colostate.edu/topic-areas/yard-garden/environmental-disorders-of-woody-plants-2-932/
I am including information about ips and Mountain Pine Beetle,
you can carefully check your tree for pitch tubes, boring holes and sawdust around the tree. Bark beetles typically attack pine or spruce that are stressed.
https://csfs.colostate.edu/forest-management/common-forest-insects-diseases/mountain-pine-beetle/
https://extension.colostate.edu/topic-areas/insects/mountain-pine-beetle-5-528/
https://extension.colostate.edu/topic-areas/insects/ips-beetles-5-558/
https://csfs.colostate.edu/forest-management/common-forest-insects-diseases/ips-beetle/
Another disease to consider is Pine Wilt/Pinewood Nematode (PWN). PWN is a fatal disease of Scots and Austrian pines which have no defense against this disease. The progression of this disease begins with the needles turning grey-green to tan, eventually to brown. Colonization of the nematodes can begin in June or July. This disease can only be confirmed by sending a sample up to the CSU Plant Diagnostic Clinic located in the Denver area. I am sending information about PWD so you can compare the information with what is happening to your tree. If your tree has Pine Wilt, it should be removed to help prevent further spread by pine sawyers. If you would like a tree sample tested for PWD, you can contact the lab directly.
https://agsci.colostate.edu/agbio/plantclinic/
https://extension.colostate.edu/topic-areas/yard-garden/pine-wilt-disease-2-915/
I am including information about how to select an arborist in case you are interested.
https://www.treesaregood.org/
Thank you,
Thank you for your additional pictures and information, very informative. You describe the declining tree as being discolored with budding suddenly stopped. Would you describe the color as turning grey green? It looks like the tree is producing new cones. The whitish area around the new cones looks to be a normal process of cone development. The needles on the tree look healthy.
https://www.waterwiseplants.org/find-a-plant/austrian-pine/
I have some questions to ask you to help narrow down the cause of your tree's decline. I have noticed that the area around the trees is surrounded by wood and rock mulch plus sidewalks. I see no weeds in the area. Is there landscape fabric under the mulch? Has any construction occurred in the area that could damage the trees roots. Do the trees receive supplemental irrigation or have any fertilizers, pesticides or herbicides been used in the area. Austrian pines require a moderate amount of irrigation.
Here is some information from OSU about abiotic damage to Christmas trees. Different types of damage can be selected.
https://pubs.extension.oregonstate.edu/pnw659/fertilizer-burn
I am sending Environmental Disorders of Woody Plants, please note the drought section. I do not see drought symptoms on your pine.
https://extension.colostate.edu/topic-areas/yard-garden/environmental-disorders-of-woody-plants-2-932/
I am including information about ips and Mountain Pine Beetle,
you can carefully check your tree for pitch tubes, boring holes and sawdust around the tree. Bark beetles typically attack pine or spruce that are stressed.
https://csfs.colostate.edu/forest-management/common-forest-insects-diseases/mountain-pine-beetle/
https://extension.colostate.edu/topic-areas/insects/mountain-pine-beetle-5-528/
https://extension.colostate.edu/topic-areas/insects/ips-beetles-5-558/
https://csfs.colostate.edu/forest-management/common-forest-insects-diseases/ips-beetle/
Another disease to consider is Pine Wilt/Pinewood Nematode (PWN). PWN is a fatal disease of Scots and Austrian pines which have no defense against this disease. The progression of this disease begins with the needles turning grey-green to tan, eventually to brown. Colonization of the nematodes can begin in June or July. This disease can only be confirmed by sending a sample up to the CSU Plant Diagnostic Clinic located in the Denver area. I am sending information about PWD so you can compare the information with what is happening to your tree. If your tree has Pine Wilt, it should be removed to help prevent further spread by pine sawyers. If you would like a tree sample tested for PWD, you can contact the lab directly.
https://agsci.colostate.edu/agbio/plantclinic/
https://extension.colostate.edu/topic-areas/yard-garden/pine-wilt-disease-2-915/
I am including information about how to select an arborist in case you are interested.
https://www.treesaregood.org/
Thank you,
Thank you for your response. I would say the color of the tree is light green or yellowish green compared to the dark green one in the background. The new cones started, but it has suddenly stopped and they are not getting any bigger. There is landscape fabric and I also applied Preen to the rock area, but not the mulch area. I suppose some of the Preen could have leeched to the roots of the tree. We have also received some heavy rain this spring and that may have affected this tree.
Hi Michael,
Thank you for letting me know that there is landscape fabric under the mulch. You feel that our heavy rain could be affecting your tree. The landscape fabric may be preventing normal air and water exchange through the fabric. Excess water in the soil or reduced oxygen can cause oxygen starvation. I am including a couple of articles and quotes.
https://cmg.extension.colostate.edu/Gardennotes/331.pdf
"Oxygen starvation occurs when excess water in the soil drives out oxygen, causing the “suffocation” of roots. Plants respond by dropping lower leaves that are usually yellowed or necrotic. Leaf loss is most noticeable from the inside of the plant out and the bottom up. In addition, leaves may be smaller than normal, growth increments may be small, and the plant may have an overall unthrifty appearance. While oxygen starvation causes root damage, the first clue that something is wrong appears on the canopy, stems, and branches. These parts are the furthest from the water source, so the symptoms appear there first."
https://extension.colostate.edu/topic-areas/yard-garden/mulches-for-home-grounds-7-214/
"Black plastic (polyethylene) and woven plastic weed barrier fabrics (polypropylene) are not recommended as a mulch in landscape areas. Black plastic is impermeable therefore no oxygen exchange can occur to the soil. Lack of oxygen to the roots and soil microbes significantly reduces plant growth. Black plastic also prevents water penetration. Woven weed barrier fabrics initially allow some minor oxygen and water exchange to the soil, but eventually become clogged and create the same issues as plastic."
You can check the amount of moisture in the soil by peeling back some of the fabric to check moisture or inserting a screwdriver or house plant moisture meter through the fabric and pushing the probe into the soil.
https://extension.colostate.edu/topic-areas/yard-garden/watering-a-home-landscape-during-drought-7-240-2/
"One technique to assess soil moisture is to use a 6-inch screwdriver to probe the soil. If the screwdriver inserts into the soil easily, water is often not required. Be aware that sandy soils generally do not exhibit high resistance to penetration and may need water even if screwdriver insertion is effortless. Another method to measure the soil’s moisture level is to use a standard indoor/outdoor moisture meter. Keep in mind, however, that soils high in organic matter will typically result in a higher moisture reading even though not all of the moisture may be available to the plant."
Here is an interesting article about landscape fabric from the University of Illinois.
https://extension.illinois.edu/blogs/good-growing/2021-06-25-disadvantages-landscape-fabric
Best Regards,
Thank you for letting me know that there is landscape fabric under the mulch. You feel that our heavy rain could be affecting your tree. The landscape fabric may be preventing normal air and water exchange through the fabric. Excess water in the soil or reduced oxygen can cause oxygen starvation. I am including a couple of articles and quotes.
https://cmg.extension.colostate.edu/Gardennotes/331.pdf
"Oxygen starvation occurs when excess water in the soil drives out oxygen, causing the “suffocation” of roots. Plants respond by dropping lower leaves that are usually yellowed or necrotic. Leaf loss is most noticeable from the inside of the plant out and the bottom up. In addition, leaves may be smaller than normal, growth increments may be small, and the plant may have an overall unthrifty appearance. While oxygen starvation causes root damage, the first clue that something is wrong appears on the canopy, stems, and branches. These parts are the furthest from the water source, so the symptoms appear there first."
https://extension.colostate.edu/topic-areas/yard-garden/mulches-for-home-grounds-7-214/
"Black plastic (polyethylene) and woven plastic weed barrier fabrics (polypropylene) are not recommended as a mulch in landscape areas. Black plastic is impermeable therefore no oxygen exchange can occur to the soil. Lack of oxygen to the roots and soil microbes significantly reduces plant growth. Black plastic also prevents water penetration. Woven weed barrier fabrics initially allow some minor oxygen and water exchange to the soil, but eventually become clogged and create the same issues as plastic."
You can check the amount of moisture in the soil by peeling back some of the fabric to check moisture or inserting a screwdriver or house plant moisture meter through the fabric and pushing the probe into the soil.
https://extension.colostate.edu/topic-areas/yard-garden/watering-a-home-landscape-during-drought-7-240-2/
"One technique to assess soil moisture is to use a 6-inch screwdriver to probe the soil. If the screwdriver inserts into the soil easily, water is often not required. Be aware that sandy soils generally do not exhibit high resistance to penetration and may need water even if screwdriver insertion is effortless. Another method to measure the soil’s moisture level is to use a standard indoor/outdoor moisture meter. Keep in mind, however, that soils high in organic matter will typically result in a higher moisture reading even though not all of the moisture may be available to the plant."
Here is an interesting article about landscape fabric from the University of Illinois.
https://extension.illinois.edu/blogs/good-growing/2021-06-25-disadvantages-landscape-fabric
Best Regards,
