Brush pile under tree hastened blooming, possibly providing warmer microclimate?

I was driving out of my driveway this morning and noticed my neighbor's blooming pear tree that had blossoms on one small area opening, but the rest hadn't bloomed yet.

Under that section of the tree there was a brush pile about 5 ft  high and wide and 10 ft long.

It appears that the brush pile my have created a warmer microclimate that caused the blossoms above it to open before the ones on the rest of the tree.

I have some Japanese plum trees that bloom very early in the year and almost always get hit hard from late frosts, but I keep them to hopefully be able to save the seeds from them and develop varieties that bloom later. I was thinking that this observance above may be a way to help keep the the area warmer on cold nights to minimize frost damage.

Has anyone else seen anything like this?

It's commonly discussed that high-sloped upper hillsides, riverbanks, and rock mounds do the same thing(collect and expel solar energy as localized heat). I don't see why a tall, dark wood/brushpile wouldn't do the same thing.  It's also acting as mulch on the soil below, so it's a double-effect!
Paul further demonstrated this as a browse deterrent for deer in one of his videos - triple-effect!  

Why aren't we all doing this?

Dustin Rhodes wrote:It's commonly discussed that high-sloped upper hillsides, riverbanks, and rock mounds do the same thing(collect and expel solar energy as localized heat). I don't see why a tall, dark wood/brushpile wouldn't do the same thing.  It's also acting as mulch on the soil below, so it's a double-effect!
Paul further demonstrated this as a browse deterrent for deer in one of his videos - triple-effect!  

Why aren't we all doing this?

Those are great points Dustin!

Just to double check...  The brush pile is under the part of the tree that bloomed earlier?  So the brush is hastening blooming and hopefully also protecting those blooms from ensuing frosts due to thermal storage and radiation.  

Mike Jay wrote:Just to double check...  The brush pile is under the part of the tree that bloomed earlier?  So the brush is hastening blooming and hopefully also protecting those blooms from ensuing frosts due to thermal storage and radiation.  

Yeah, that's what I'm thinking!

I'm thinking the mulch will not protect the flowers from later frosts, if any occur this year, and the mulch sounds like it is promoting early blooming rather than delaying bloom, if I understand your posts.

Old-time tactics to delay bloom are to plant on north facing hills with no mulch, to encourage the tree to stay dormant longer and thereby (hopefully) avoid late frosts

Hope you follow up on this tree and how it fares this spring, mulched side vs unmulched side.  

Myrth brings up a good point - why bloom them earlier on purpose if they still may die?

Sounds like IF they are already blooming early though, a brush pile MIGHT further protect them (some percentage chance) more than without mulch if there is another frost?

I'm guessing it's a balance.  If you have a tree that needs as many growing days as possible to set fruit, and if your late frosts can be overcome with the protection of a brush pile, it could benefit you by both hastening blooming and then by protecting those blooms.

And it sounds like you could always do half of each tree with a brush pile and then you hedge your bets.

Sorry everyone, I think my brain was a little scrambled after a long day at work, and the title was confusing. I updated the title to convey what I actually meant to say.

Myrth Montana wrote:I'm thinking the mulch will not protect the flowers from later frosts, if any occur this year, and the mulch sounds like it is promoting early blooming rather than delaying bloom, if I understand your posts.  

I wander if a little mulch might be helpful, for the health of the tree, and also to help keep the soil cooler on hotter days in the early spring to slightly delay blooming?

Maybe this bigger brush pile is storing more heat which is causing the section above it to bloom so early? It is mostly large branches with leaves mixed in and some on the top. I wander if the air inside it is warmed by the dark leaves and then is released throughout the night?

Maybe it could be put there, which hopefully could be convenient and not a major job, after blooming begins, and could help slightly protect the blooms from late frosts?

Lots of ifs, should be interesting though!

Mulching trees is always a good idea for moisture control.

Brush piles can create microclimates but the brush would need to be piled in fairly thick so as to adsorb the most sun driven heat it could hold.
If you did such a construction it would give you the opportunity later on to turn it into a hugel mound/ heat sink for the tree(s) it was protecting.

Redhawk

Steve, can you post a photo of it?  In case people want to copy it?

Mike Jay wrote:I'm guessing it's a balance.  If you have a tree that needs as many growing days as possible to set fruit, and if your late frosts can be overcome with the protection of a brush pile, it could benefit you by both hastening blooming and then by protecting those blooms.

And it sounds like you could always do half of each tree with a brush pile and then you hedge your bets.

Awesome observations Mike!

Steve, can you post a photo of it?  In case people want to copy it?

Yeah Mike, I'll try! I can see it from the street, but it's kinda in the middle of my neighbor's yard, so it might be a little difficult to do unless I just walk over there!

Would a leaf pile have a similar effect? Put a leaf pile on the south side of the tree, when the bags of leaves get hauled to the street (suburb guy here) and let them break down over the winter. Spring rains could help store the heat so when a light frost comes the pile radiates the heat above.  Sorry maybe over thinking this.

It might work with leaves.  But they could start composting and if they're touching the trunk it might hurt the tree?  But composting could generate heat as well...  What about a simple compost bin to keep the leaves a few inches away from the trunk and to help the leaf pile get tall (closer to the branches)?

I have leaves in my chicken run and I've been adding lots of coffee grounds to them.  They're composting very hot and it's -5 to 30 degrees out.

I have started wrapping the base of my trees with hardware cloth.  I am thinking that as long as I keep a distance between the tree base and the chips (3 to 4 inches away), it should be okay.  That way I can pile higher and closer and still keep moles/voles away.  Hopeful anyway.  
Hardware cloth may be a bit expensive but I can chop the rolls into numerous lengths and provide a little overlap so when the tree grows I can make it larger.

Here is a picture of my jujube wraps.  These are a little closer and maybe 2 inches away but as the tree grows I can expand.

Steve Thorn wrote:I was driving out of my driveway this morning and noticed my neighbor's blooming pear tree that had blossoms on one small area opening, but the rest hadn't bloomed yet.

Under that section of the tree there was a brush pile about 5 ft  high and wide and 10 ft long.

It appears that the brush pile my have created a warmer microclimate that caused the blossoms above it to open before the ones on the rest of the tree.

I have some Japanese plum trees that bloom very early in the year and almost always get hit hard from late frosts, but I keep them to hopefully be able to save the seeds from them and develop varieties that bloom later. I was thinking that this observance above may be a way to help keep the the area warmer on cold nights to minimize frost damage.

Has anyone else seen anything like this?

I agree that the mulch  being darker could absorb heat that can help the area be warmer. Another factor that may come into play is the fact that when you have organic matter being digested they create heat. Also, mulch being much lighter than dirt and having more air pockets, has a much greater R-value keeping the soil from getting cold. For instance, 4 inches of concrete has only about half of 1 R-value, while wood has an R-value of approximately one R per inch. If it was rotting away It would go more spongelike thus increasing its R-value even better than solid wood plus it being wood chips already has a lot of air gaps so it definitely is going to keep your ground much better than plain dirt.  
When I was young in an agricultural community that I grew up in, one of my neighbors harvested hay. It had been recently rained on his hay. The moisture in the hay caused it to mold and invited a lot of heavy bacteria to live in it.
He mounted it up in his barn and as time went on that moisture in the hay made a perfect place for it to start molding and rotting away. The heat given off by the moldy hay was enough for it to auto combust and burn down the hay in the barn.

Also there is a gentleman, I believe he was out of France, and he would use hay piles and mulch piles  of wood chips that were built over coils of poly propylene tubing and had water pumping through the tubing. With enough of the tubing touching enough mulch, it produce enough heat that he did not need to do anything else to get his water hot. And he used it to heat his home by pumping the hot water into his home into a radiant floor type system. He also used it for his domestic use needs for hot water.

Dustin Rhodes wrote:It's commonly discussed that high-sloped upper hillsides, riverbanks, and rock mounds do the same thing(collect and expel solar energy as localized heat). I don't see why a tall, dark wood/brushpile wouldn't do the same thing.  It's also acting as mulch on the soil below, so it's a double-effect!
Paul further demonstrated this as a browse deterrent for deer in one of his videos - triple-effect!  
Why aren't we all doing this?

More specifically with the influence of mulch over blooming: The timing of the mulching is crucial: If you mulch *after* the ground is frozen, then you place insulation over the frozen ground, which would have the effect of *delaying* the start of the season since the sun would have to warm the frozen mulch first, then the frozen ground. That is important if you wish to delay flowering because we always get late frosts.
Placing insulation over unfrozen ground will delay the freezing of the ground, and over the months of winter will protect some perennials if the ground is not allowed to freeze too deep. To get the best of both, you may want to apply mulch to strawberries early in the fall, but remove it as soon as the snow is gone to wake up the bed to the effects of spring.

John Barlow wrote:I agree that the mulch  being darker could absorb heat that can help the area be warmer. Another factor that may come into play is the fact that when you have organic matter being digested they create heat. Also, mulch being much lighter than dirt and having more air pockets, has a much greater R-value keeping the soil from getting cold. For instance, 4 inches of concrete has only about half of 1 R-value, while wood has an R-value of approximately one R per inch. If it was rotting away It would go more spongelike thus increasing its R-value even better than solid wood plus it being wood chips already has a lot of air gaps so it definitely is going to keep your ground much better than plain dirt.  
When I was young in an agricultural community that I grew up in, one of my neighbors harvested hay. It had been recently rained on his hay. The moisture in the hay caused it to mold and invited a lot of heavy bacteria to live in it.
He mounted it up in his barn and as time went on that moisture in the hay made a perfect place for it to start molding and rotting away. The heat given off by the moldy hay was enough for it to auto combust and burn down the hay in the barn.

Also there is a gentleman, I believe he was out of France, and he would use hay piles and mulch piles  of wood chips that were built over coils of poly propylene tubing and had water pumping through the tubing. With enough of the tubing touching enough mulch, it produce enough heat that he did not need to do anything else to get his water hot. And he used it to heat his home by pumping the hot water into his home into a radiant floor type system. He also used it for his domestic use needs for hot water.

Interesting info John!

I think I may try to do some things like you mentioned above and also try to recreate the brush/leaf pile like my neighbor's at my house and take a picture of it.

It's supposed to get down into the teens here this weekend and I've got one plum in full bloom. I'm going to need to maintain and possibly create some additional heat at this point to try to get it through these hard cold spells before spring.

Awesome observations
Sounds a lot like hugelstyle 101 to me.
If we recreate the rainforest floor I believe there is no limit to our soils potential to provide.
Happy Hugel

Cécile Stelzer Johnson wrote:More specifically with the influence of mulch over blooming: The timing of the mulching is crucial: If you mulch *after* the ground is frozen, then you place insulation over the frozen ground, which would have the effect of *delaying* the start of the season since the sun would have to warm the frozen mulch first, then the frozen ground. That is important if you wish to delay flowering because we always get late frosts.
Placing insulation over unfrozen ground will delay the freezing of the ground, and over the months of winter will protect some perennials if the ground is not allowed to freeze too deep. To get the best of both, you may want to apply mulch to strawberries early in the fall, but remove it as soon as the snow is gone to wake up the bed to the effects of spring.

That's a good observation Cecile!

I'm going to experiment next year and add extra mulch also right after blooming begins, hopefully to get the latest bloom time possible and then keep it warmer while trying to get through the late cold snaps.

C Gale wrote:Awesome observations
Sounds a lot like hugelstyle 101 to me.
If we recreate the rainforest floor I believe there is no limit to our soils potential to provide.
Happy Hugel

Very true C Gale! Go hugels!

Also there is a gentleman, I believe he was out of France, and he would use hay piles and mulch piles  of wood chips that were built over coils of poly propylene tubing and had water pumping through the tubing. With enough of the tubing touching enough mulch, it produce enough heat that he did not need to do anything else to get his water hot. And he used it to heat his home by pumping the hot water into his home into a radiant floor type system. He also used it for his domestic use needs for hot water.

Jean Pain. Here’s a pdf download. Really fascinating

https://ia800202.us.archive.org/8/items/Another_Kind_of_Garden-The_Methods_of_Jean_Pain/Another_Kind_of_Garden-The_Methods_of_Jean_Pain.pdf

To continue this discussion a little longer. What if you put down a large pile of mulch after a hard freeze, water the mulch before the next freeze and then get some white shade cloth to cover over the chips?  
I really need to find a way to stop my kiwi (A. Chinensis) from blooming so early.
Maybe even add a heavy shade cloth over the top of the pergola to keep the vines from getting warm.

Dennis Bangham wrote:To continue this discussion a little longer. What if you put down a large pile of mulch after a hard freeze, water the mulch before the next freeze and then get some white shade cloth to cover over the chips?  
I really need to find a way to stop my kiwi (A. Chinensis) from blooming so early.
Maybe even add a heavy shade cloth over the top of the pergola to keep the vines from getting warm.

In Alabama, would you need to prevent early blooming? When is your A. Chinensis flowering and can you still expect frosts at that time? [hard blossom killing frosts?] Here in Wisconsin, we can expect hard frosts until Memorial Day and the garden does not get its first tomato plant planted before then. And even then, we have to be ready to cover.
The treatment you describe definitely would delay blooming. The best way to retard it might be if you could place blocks of ice by the roots and then add wet mulch: They sell blocks of ice in plastic sacs in convenience stores. That would work slick if you were to place 2-3 bags of it by each plant.
In Europe, at the time of Louis XIV, and even more recently in Wisconsin and Canada, folks had an interesting way of producing ice cream in summer or preserving ice, long before the time of refrigerators: They would go on the local frozen ponds/ lakes in the winter and cut and lift chunks of ice the thickness of the ice. It was backbreaking work, done with mules or horses. Then they would cover them with a thick layer of wood chips or wet straw. with a good layer of insulation, the ice would not melt until June-July and the King could have his ice cream. It was also a way to preserve cleaned fresh fish and bring it to market a little distance inland before the advent of refrigerated trucks. So, yes, insulating snow should work (ice will work even better: snow is too fractured, so your idea to wet the mulch is superior)
https://recollectionwisconsin.org/ice-harvesting
I know I'm dating myself, but I can still remember my mom having an ice-box and cussing at the ice man who had delivered chunky ice instead of blocks: [fractured ice melts a lot faster].
The next thing you may have to worry about is the pollination process: Pollinating insects work in sync with the seasons and the sun. Artificially delaying blooming may have bad consequences if the pollinators season does not match the growing season, especially if the A. Chinensis has a short blooming period before fecundation.
That is one of the things we will have to think about with global warming: The pollinators being ready before the blooms are or vice-versa. When there is a mismatch, they both suffer.
Shading the pergola will also help but may be overkill IMHO. [How much pergola cover would you have to buy relative to the amount of fruit you could get from the vines?]
I hope you are successful in your tinkering with delaying blooming. Let us know how that works. To make it more 'scientific', you would have to treat some this way and allow others  to go without treatment

We do not plant until mid April which historically was after last frost. But everything keeps blooming too early now.  I am wondering if the vines getting warm is causing the early bloom.  I have several inches of wood chips down and I expect the ground to be very cool.  I do not have a way to measure ground temps.
I do have Hardy Kiwi which seems to do okay over the light frosts but the Fuzzy gets knocked hard.  In fact there was no frost for the last couple of nights and slightly above freezing but the leaves that had sprouted on my A. Chinensis are dried and crinkly.  
I have not seen many pollinators yet.  A few flies and only now some bumble bees.  I need to attract more solitary bees.  
My kiwi are still young and only a few have reached the pergola wires.  I have ordered another female that hopefully will handle the cold better.  It is a new release called Gold Coast from Auburn University.  I will try various different fuzzy males to pollinate.  

Dennis Bangham wrote:To continue this discussion a little longer. What if you put down a large pile of mulch after a hard freeze, water the mulch before the next freeze and then get some white shade cloth to cover over the chips?  
I really need to find a way to stop my kiwi (A. Chinensis) from blooming so early.
Maybe even add a heavy shade cloth over the top of the pergola to keep the vines from getting warm.

I think shade could possibly help.

Maybe it could be planted in a spot too that receives winter shade but summer sun.

Dennis Bangham wrote:We do not plant until mid April which historically was after last frost. But everything keeps blooming too early now.  I am wondering if the vines getting warm is causing the early bloom.  I have several inches of wood chips down and I expect the ground to be very cool.  I do not have a way to measure ground temps.
I do have Hardy Kiwi which seems to do okay over the light frosts but the Fuzzy gets knocked hard.  In fact there was no frost for the last couple of nights and slightly above freezing but the leaves that had sprouted on my A. Chinensis are dried and crinkly.  
I have not seen many pollinators yet.  A few flies and only now some bumble bees.  I need to attract more solitary bees.  
My kiwi are still young and only a few have reached the pergola wires.  I have ordered another female that hopefully will handle the cold better.  It is a new release called Gold Coast from Auburn University.  I will try various different fuzzy males to pollinate.  

They sell a thermometer you plunge in the ground to check the temperature. Your local garden center ought to have that and I don't think they are expensive. I know nothing about the fuzzy kiwi which just cannot make it here.
Yep. That is what I was talking about. In spite of a grueling and harsh winter here *this* year, the trend is clearly toward temperatures rising overall and the blooming arriving earlier, before your bumble bees are ready. I think that plant can adapt faster to rising temperatures, but bugs will take longer. That is just my opinion, unverified. I'm not sure how fast the ice would melt but it is worth a try to place 2 or 3 sacs of block ice and a lot of wood chips or better, sawdust to delay pollination.
Another problem, which has been documented is that when the CO2 rises above 400 parts p. million, [and it has not gone down below this since 2013] the nutritive balance of the pollen is altered [The sugars rise but the protein goes down]. Since insect pollinators count on the pollen to have enough protein to raise their brood, plus we have a lot of mono-culture [potatoes or corn or soy], these insects cannot find enough protein in the little pollen they do harvest. The mismatch in flowering time just make it worse.
The last 2 years, I found a couple of hive beetles at harvest time. That had never happened before. They had survived the winter in the hive. One of my beekeeping friends who raises cranberries confided that this year, she had fed her bees the entire year. [Cranberries make absolutely no nectar and very little pollen, so it is always a battle to keep her bees alive anyway. But having to feed them? First time I hear that.]