Dead Leaves/Frost

[jdj]

Where I live(northern, NY) it appears that the frost this past week has killed most of the leaves on the maple trees:mad: . I'm just wondering if any other areas have been affected by the unseasonable cold weather? Also what negative affects can be expected? Will the trees re-bud and leaf out again?

[Russell Lampron]

Time will tell but one summer the leaves on my wife's crab apple tree fell off because of a drought. That was in August. The tree rebudded and grew more leaves in September when it started raining. I thought the tree was dead but it still lives in the back yard now. Keep us posted, I would like to know if your leaves come back or if they are done for the season.

[DrTimPerkins]

Where I live(northern, NY) it appears that the frost this past week has killed most of the leaves on the maple trees. <snip> Also what negative affects can be expected? Will the trees re-bud and leaf out again?

We had some light-moderate damage in areas in Underhill Center, VT (1,400+ ft elevation) as well. Only the second time in my adult life that I can remember seeing frost damage to maple leaves. Last time was in 1983 or 1984 (I think), but fairly high in the hills and sporadic on that occasion.

If the damage to any individual tree is light-moderate, the trees will get by with the leaves they have. If the damage is heavy-severe (near-complete loss of foliage), the tree will reflush a new set of leaves in the next several weeks to a month.

Defoliation is always stressful to plants. It uses up a lot of their carbohydrate reserves to grow a set of leaves. Having to do it twice is costly in terms of energy. If this growing season is good and the trees were otherwise healthy, it should be OK. If the trees were in marginal-poor health to begin with, or had some other moderate-heavy stress factors, they could show some crown decline over the next several years. Interestingly a heavy seed crop will do the same thing (deplete carbohydrate reserves), so trees can cope with these occasional, single, heavy stresses. It is when you start piling 2-3 moderate-heavy stresses on top of one another that you see problems.

Smaller trees, especially if they haven't reached full canopy status are the most vulnerable. Their growth rates can be marginal as is (living in the dark understory is a quite stressful).

Hope for a good growing season (no droughts, no insects, good moisture, plenty of sun). If it isn't great, lighten up on tapping if you can.....especially on the smaller trees.

[argohauler]

I've always wondered if vacuum would take too much out of a tree. Has anybody noticed any changes to the trees on drought years?

[wally]

better to have the leaves drop early in the season, rather than in mid-summer. then the tree has virtually the whole growing season to recover. also, i don't consider a heavy frost in the first half of may to be "unseasonably cold". there's a very good reason why yankee farmers didn't plant their gardens until the last full moon in may. what was unseasonable was the march/april weather that caused so many trees to flush vegetation about one month earlier than average.

all things being equal, the tree is much better off having to re-flush in may vs having to reflush in july or early august.

[DrTimPerkins]

I've always wondered if vacuum would take too much out of a tree. Has anybody noticed any changes to the trees on drought years?

Probably not a problem unless you tap small trees (under 6" dbh) and use high vacuum and are getting > 0.5 gal syrup/tap.

We have an on-going project looking at this very question. Will take several years to get a real good answer, but early indications are that under conservative tapping practices (10" dbh trees for first-tap, 18" for 2 taps), there is not a problem. Ask again in 2013.

Before anyone gets bent out of shape, we do realize that some people tap smaller trees, and that is OK as long as you intend to do some thinning to release your potential crop trees. You should NOT tap the young potential crop trees though. Leave those alone. But for those young trees that are going to be thinned anyhow, I have no problem with folks tapping them.

We generally tap our production trees at 11-12" dbh. We do tap some smaller trees for research purposes though (largely because the larger trees are tapped for production), and often will tap small trees when we know we're going to be cutting them down to look at the internal staining. Doesn't make sense to cut down a huge tree just to look at the effects of one taphole on staining. We'd run out of trees quickly if we did that.

Drought is probably one of the biggest stresses to trees in the forest, but typically causes decline only in susceptible sites (shallow, stoney soils). Usually there is only a problem with you have interacting stresses (drought + insects, drought + heavy tapping, drought + ice storm damage, etc.).

[DrTimPerkins]

<snip>all things being equal, the tree is much better off having to re-flush in may vs having to reflush in july or early august.

Absolutely correct. This is because it takes a lot of energy to fully build a leaf and get it to the point where it is producing sugars. If they're injured at this point, maybe 50-75% of the total energy to get that leaf up to its full potential has been spent. It takes some time before the leaf is actually a net exporter of sugar. Worst case would be if it gets eaten/damaged immediately after it is fully developed. At that point there would have been 100% investment of energy in the leaf, but no gain.

Interestingly it may not affect radial (stem) or apical (twig) growth much this year, but might next (depending how things play out). This is because a good amount of stem growth has already taken place this year, and is fueled in large part by carbohydrate reserves already in the tree.

I'm going to make maple physiologists out of all of you yet!

[adk1]

Dr. I will be tappign alot of the 10" dia trees and I do not plan on thinning them at all. I will consider them as my sugarbush. Is this ok? I plan on usign the 5/16" spouts on bags only, no vac. some of them maybe 9" too

[wally]

I'm going to make maple physiologists out of all of you yet!

please no. :lol:

i'm content with forestry as an avocation, and sugaring as a hobby.

[DrTimPerkins]

Dr. I will be tappign alot of the 10" dia trees and I do not plan on thinning them at all. I will consider them as my sugarbush. Is this ok? I plan on usign the 5/16" spouts on bags only, no vac. some of them maybe 9" too

All depends....trees need room to grow. If they're too thick, you'll have poor radial growth. Poor radial growth eventually yields coalescing tap stain zones. This is the main bad consequence of people not burning wood.....there is much less need for people to cut regularly. Even if you burn oil or wood scraps you get elsewhere, you still need to be committed to proper crop tree management (in my opinion). The first step for us in every tubing project is to thin the woods....it'll be 10-20 years before we can get in there again. The time to do it is before your tubing is installed (yes....I know you're not doing tubing).

There are really two factors in play here: wounding/staining and carbohydrate extraction.

With gravity sap extraction, you needn't really worry about taking too much sap from a tree as long as it isn't really small. You do need to be concerned about having growth rates that are good enough to mitigate against stained areas caused by tapping getting too large/merged to the point where you impact water movement in the tree and reduce sap yields due to lack of conducting sapwood.

With vacuum, you need to also factor in the possibility of excess carbohydrate extraction. Unfortunately we don't know enough about this at the current time to make recommendations, other than don't tap really small trees with high vacuum systems (unless you're going to cut them down next time you thin).

We do hope to have some much better (and scientifically valid) recommendations than those that currently exist within the next 2-4 years.

There is little reason to use anything but 5/16" spouts, unless you already have 7/16" spouts and can't afford to change (hobby). Plenty of argument to be made that if you are using 7/16" spouts (non-hobby) that changing things could actually save you money and result in healthier trees.

[wally]

There is little reason to use anything but 5/16" spouts, unless you already have 7/16" spouts and can't afford to change (hobby). Plenty of argument to be made that if you are using 7/16" spouts (non-hobby) that changing things could actually save you money and result in healthier trees.

we're a hobby, but we changed over to the 19/64" completely by 2007, appx. 230 taps, and we have another 150+ brand new 19/64" taps to be used for replacing installed taps as they get damaged. really no reason why even hobbyists can't change over. the cost for the taps is pretty minimal at the hobby level.

[adk1]

I would agree. I am actually thinning are the moment, one side....I beleive the maples are pretty old but havent had the chance to recieve alot of light due to the dominating pines etc..

[DrTimPerkins]

You do need to be concerned about having growth rates that are good enough to mitigate against stained areas caused by tapping getting too large/merged to the point where you impact water movement in the tree and reduce sap yields due to lack of conducting sapwood.

Somebody sent me an email asking that I expand this explanation.


What happens to the tap area and how big is this area in the wood? Is it dead for good, or just till the tap hole closes? Do you have to have new wood growth over a tapped area that is, say 1.5" thick, till you tap that area again?

The stained area varies from tree-to-tree and upon obvious things like depth of taphole and width of taphole (size of spout). Normally it extends about a foot above and a foot below the taphole, is just a little wider and a little deeper than the taphole, and tapers both upward and downward somewhat.

The staining is caused by the tree "walling off" the wound to prevent fungi and other microorganisms from infecting the tree (through the wound). The taphole itself never fills in. The stained wood area is pretty much impervious to the movement of water/sap and is also non-functional from the standpoint of carbohydrate (starch/sugar) storage. As far as the tree is concerned physiologically, that part of the tree is gone and plays no other role except to hold the tree up.

One misconception is that wood is "dead". The majority of wood cells are dead, but functional (wood vessels move water/sap even though dead). However there are also a large number of living cells in wood that do have other functions.

When overtapping occurs, the stained areas within a tree can occupy a large portion of the interior of the tree, leaving only a small band of functional sapwood (wood that moves sap/water and stores carbohydrates). This impacts the ability of the tree to move water up to the crown during the summer, and also limits the ability of the tree to store sugars (in effect, the "pantry" to store food is smaller).

The thinking behind "sustainable" tapping is to never "remove" (meaning to make non-functional) a volume of wood from the tapping band of the tree larger than the tree can regrow in the succeeding growing season.

Cluster tapping does the same sort of thing, but extends to the exterior of the tree where a portion of the cambium and phloem is also killed.

[3rdgen.maple]

Okay Dr.Perkins now in laimans terms can you give us your best recomendations on tapping practices. Like what is your smallest recomended tree to tap for production and not culling, do you have a recomendation as to tap hole placement from season to season, tap hole depth? For both vac and gravity. I will not hold it against you if I follow your advice and all my trees die lol.

[Amber Gold]

If the growing season has been extended 2 weeks to a month due to spring arriving earlier and winter coming later, how come our sap isn't sweeter? Stands to reason the sap should be sweeter if the leaves are on the trees longer.

[3rdgen.maple]

Im just taking a guess amber but I think mother nature tends to find a balance. I know here spring has come early but I dont think the trees leafed out any sooner and it has been mostly cloudy or raining alot this spring and without the sunshine the trees are not gaining any sweetness. But like a I said just a guess.

[wally]

If the growing season has been extended 2 weeks to a month due to spring arriving earlier and winter coming later, how come our sap isn't sweeter? Stands to reason the sap should be sweeter if the leaves are on the trees longer.

a one- or two-week gain would likely have imperceptible impact on sugar content. that, and the increase should in theory occur in the spring following the "longer" growing season. last year's spring didn't arrive early.

in this region of nh, most hardwoods leafed out about 2 weeks early, some more (red maple), some less (white ash).

[3rdgen.maple]

She who must be obeyed pointed out to me last week that the black walnut trees and the ash trees all died. It was not until the begining of this week until they budded. But back to the original thread question we were lucky to not see any significant frost damage here but when we had the tent worms devastate out foilage for 3 years in a row all but a few sugars did not make it and the 6 or so that didnt were what I would have considered the cream of the crop. Throughout those years the trees kept trying to releaf a few times during the summer. We could only tap the reds that they never touched.

[heus]

Around here the trees that have mostly leafed out do not appear to have been affected by the frost. The trees that are just now starting to leaf out (hickory, ash, sycamore) are the ones with burned leaves. One interesting thing that I noticed at the place where I used to live is the hickory trees that had leaves that were damaged by frost and had to re-leaf ended up looking much more healthy later in the summer. The ones that leafed out early and didn't get frost damaged always looked sick with bug damage and yellow edged leaves as the summer progressed. Not sure about with sugar maples, but I think the frost actaully benefitted the hickory trees.
The grape growers along Lake Erie here have seen as much as 90% of their grape crop ruined for this year by those two days of heavy frost.

[DrTimPerkins]

If the growing season has been extended 2 weeks to a month due to spring arriving earlier and winter coming later, how come our sap isn't sweeter? Stands to reason the sap should be sweeter if the leaves are on the trees longer.

Doesn't work that way. The tree makes sugar, uses some for growth, metabolism and other things, stores most of what is left as starch, and then converts some of it back to sugar in the spring for basal growth and to fuel bud-break and early leaf growth. Just because they made more doesn't mean you'll get it.

The BEST thing you can do to maximize sugar yield in this regard is to make sure your trees have room to grow. There is a good relationship between basal (stem diameter) growth and sugar yield (sap volume and sugar content). Anything you can do to encourage growth will help. THIN your stand as needed.