Wet conditions at Pearson Creek
"The greater
part of the phenomena of nature are... concealed from us
all our lives.
There is just as much beauty visible to us in the
landscape as we are prepared to appreciate, not a grain
more...
A man sees only what concerns him."
-- Henry David Thoreau
Board of Directors Field Notes
Fall 1997
Wet conditions at Pearson Creek
The Pinetum was inspected and produced the following field notes:
Annosus root rot : Once introduced, it stays there, outlasting the pine trees. Once started, it spreads via roots from tree to tree and you can never get rid of it. More and more of it is being found in piedmont areas and its spores can be blown 10 -15 miles. An effective prophylaxis is the sprinkling of Borax (cleansing) powder on fresh cut tree stumps.
Leptographium root decline: It affects white pines in the 3 - 7 y.o. range, typically 20 -30 feet tall. It is transmitted by a weevil which inhabits the duff around the base of the tree, but it is very hard to actually find one.
Nematode Pine Wilt : Scotch pine are especially susceptible, but others can be infected if they are stressed. Rapid removal of dead trees helps. Pine wilt doesn't cause the tops of trees to die typically. They either die from the bottom up or the whole tree dies quickly. It was first identified 15 years ago.
Bark beetles (Scolydidae) : They are not likely the primary cause of decline, rather are usually secondary, even with blue stain fungus present.
Pine web worms : They attack small trees which will eventually out grow susceptibility to web-worms.
Eastern White Pine : "Ozone" damage pine maybe really was winter burn or some other kind of stress. Ozone damage should be more wide-spread. The fescue currently around these white pine is not a problem; they are capturing the location on their own (but a small fescue-clear zone can be very important, e.g., the effect of a 4 foot zone around Walnut trees versus none.
Loblolly pine in the "lower 4" ( bottom land with Pearidge soil) : no explanation for occasional dieing tops. Two trees in the wettest area (being converted to red pine) may be removed. Also consider a prescribed burn in this area in February or March.
Limber pine : Spraying for needle disease is worth-while. They have either Brown Spot or Dothistroma (Dothistroma more likely). Spray early June for either, when the needles are 1/2 length, then again two weeks later. The Dothistroma and Brown Spot look similar; they have a little glassy pimple-like fruiting body. Brown Spot has more fruiting bodies and is more aggressive than Dothistroma, which rarely kills trees (except at Pearson Creek, where Lodgepole pine have been "torched" by Dothistroma). Dothistroma develops fruiting structures late, and then, only a few. A few white dots on the limber pine needles and the sunscreens are insignificant saprophytes.
Colorado Pinyon (P. edulis) pine [specimen] : The needle disease here is more typical of Lophodermium, but it is usually secondary and doesn't attack the woody portion of the tree. Also, (in a tree with a dead top) something is moving into the cambium. So it is possibly perennial canker or at least something other than needle cast or lophodermium. Most lophodermium have a football-shaped spot on the needle. Best Rx for the time being: prune out the dead portions.
Ponderosa pine : (scraping a branch with a knife reveals black streaking). It could be scleroderus canker. (Later) a Ponderosa has some Dothistroma, but most of them look very clean. Then still later, bad Dothistroma on Ponderosa. The Dothistroma starts with a yellow spot, then a red spot, then turns black and then comes this tiny fruiting structure in it, a blister in the center of the discolored area which is shiny and then turns black in the Spring. A red band on either side of the blister is typical. The big problem is humidity and pruning helps by increasing air circulation.
Optimal spraying times : Diplodia: spray @ 1/2 candle length (April).
Brown Spot/Dothistroma: spray @ 1/2 needle length (late May); this will be approx. 3/4 candle length.
Also on Ponderosa, some really long spots are Lophodermium. Infection occurs late Summer/Fall and symptoms appear in the Spring (the reverse of other fungi).
Washoe pine [specimen] : Looks like Dothistroma.
Knobcone pine [?specimen] : Doesn't look like Dothistroma because the needle spots are not spreading and girdling the twig, as would be expected with Dothistroma. This is not necessarily a needle cast. Could be environmental injury, sucking insect (but no insect) and rust is a possibility.
Mexican Red pine (P. rudis) : Needle stripe hits about the same time as Fall (angiosperm?) color onset -- very common in Scotch pine. Fall needle drop is a clear yellow color. Pneumotrichus (?or nemacyclis) will be yellow with brown bands on it. Doesn't have the distinct spots of Brown Spot or Dothistroma. In the case in Lophodermium, there is only one species which is pathogenic. This should be sprayed in August, but really don't see this very often and don't need to spray unless one is very certain of this problem.
Red pine (P. resinosa) : Diplodia can be a problem in Red pine. Also Dothistroma. No problem thus far, but it is a good idea to prune the lower whorl or two of branches to reduce the possibility of needlecast, recommended strongly to increase air circulation. Usually occurs with crowded red pine, the lower branches die, but not happening here.
Shore pine (P.contorta contorta) : A prostrate slowly declining small tree with part of the roots pulled out of the ground: nematodes not a likely problem. Another larger listing recently dead shore pine with roots partially pulled out [specimen?] [another specimen sent later]: doesn't look like nematode disease, because the whole tree should be off color -- a sickly green color. With pine wilt, the tree typically looks slightly off color in the Spring and there is little or no growth, and then in mid-Summer, the needles fade simultaneously (but tends to progress from bottom - up and from inside - out), then the tree collapses. There are not neccessarily cerambicid holes in the bark, because the roundhead borers may feed up in the shoots and don't emerge and make holes until later, "after the fact." Also this tree is too moist to have pine wilt. Use the proximal portion of a lower major branch to check for nematodes.
Also , possible canker coming in from isolated branches or the base, but nothing seen.
Also, consider Nemacyclis(?) which causes faint brown bands of more or less uniform color. Occurs on second year needles in a very moist (especially June and July) year. Is mostly on the inner parts of the tree. Scotch pine is especially vulnerable.
Sierra Lodgepole pine (P. contorta murrayana) : Needle disease on a very small tree. It is likely Dothistroma, not yet fruiting. Also has Lophodermium on it.
Southwestern White (P. strobiformis) : Underpruning not urgent. Not much in the way of needlecast here; going to have some competition problems, but no problem with the needles.
Pitch Pine : Dead tops. Cause unknown -- canker is possible. There was a big canker epidemic in Monterey pine in California.
Jeffrey pine : Needle disease is either Brown Spot or Dothistroma. Two trees with major branch swellings- - -is Gallrust. Eastern Gallrust has an alternate host in Oaks and is harmless usually, but can be a problem, making stems or trunks break. . Western Gallrust is a pine to pine rust and can buid up really quickly, ergo remove them and burn them. It is usually not prominent, except in introduced trees (such as this entire Pinetum).
Prominent yellow stripes : some needles have Dothistroma banding, but there is definitely also something else.
Jack Pine : Brown banding on the second year needles not usually a problem. Brown spot has a longer infection period (?so may need a third application also?). Should prune dead under branches and do some thinning; lifting the clear under zone will increase air flow.
Stump diagnostics : Armillaria : white matting at the base (ground level) coming from the roots. If only in the roots, not the trunk, it may be secondary or a combination of things. But if it comes above the ground, it may be a cause of mortality.
Black Stain Root Rot : visible when you cut it and is deeper under the bark- - -black streaks at ground level. If only deeper in the roots, it is not necessarily significant.
Table Mountain Pine : One dead smaller tree [specimen] with needles with occasional yellow stripes- - - diagnosis uncertain. Some Dothistroma here. Other trees with swellings in the buds: sectioning revealed no gross evidence of insect invasion.
Eastern White Pine (nursery "sawdust" victim) with aphids. Cool it -- no problem this late in the year. Had (earlier) ladybird beetles -- the aphid eaters have a black "W" or "M" on the pronotum.