Least impact tree clearing: lots of small trees or a big one?

The lot I have my eye on is an acre of young forest.  I want to build a dome house with a minimal impact on the forest while maintaining safety for the house.

Most trees are about as big around as a coffee can to soda can size.  Some of them are pretty large.  Too big to wrap my arms around.  Those are regularly interspersed. The whole lots is that way.

I'd planned to dig a basement for the dome to get to the geothermal layer for temperature regulation.  If I did that, no matter what, I have to cut through some roots.

I see two approaches.  One is find a circle of smaller trees between bigger trees and cut them down, then dig the foundation, cutting part of the roots of the surrounding big trees and hope it isn't enough to damage them permanently.  Two is go right for a big tree, cut it down, and center the foundation on that spot, hopefully impacting fewer trees overall.

I don't really like the idea of cutting down a big tree.  But I like it a lot if it has an overall lesser impact and improves the safety of the home.Any thoughts?

Each main root is the life supply for a main branch when talking about trees.
That means that if you cut one main root of a large tree, then the connected main branch of that root will die.

In this case your best bet would be to center the house foundation over the pit left from removing one large tree, this lessens the overall impact of your build upon your wooded lot.

Thank you, Bryant!  That is what I suspected.  I hate to take down a big tree but perhaps I can use the wood inside the house.  I'll look for an already damaged tree.

Check around for someone with a good band saw lumber mill, that way you can have them make the tree into wood for your house and honor the tree by keeping it's spirit with you always.

Of course you can do what you want, and Bryant is right about the impact on roots (it generally correlates across the tree like an ‘s’, w north facing roots supplying south facing branches).  But Bill Mollison is pretty explicit that permaculture ethics do not validate cutting down established forest for doing permaculture. Taking out as little as possible and putting it to long term use may be worth it and certainly people do worse, and I am glad someone who cares enough to ask, like you, is doing it. However, in terms of impact on your watershed, wildlife and carbon balance, taking out a big tree is exponentially worse than taking out a small one. With deeper roots and exponentially more photosynthetic surface area, Larger, older trees grow much more biomass per year, even relative to acreage in evergreens. It would also be wise consider site location beyond just where a dead tree happens to be. I don’t know your climate so I don’t know if you want shade or sun on your dome, or whether the trees are deciduous or evergreen.

It seems like you care so you will be a lot better on the land than the next guy, but I just thought I’d point out the old logger fallacy about “overaged trees are mostly dead and grow slower, just look at how the rings get skinnier as they go out!” This logger fallacy that was used to validate cutting down our greatest forests is just a demonstration of geometric illiteracy, as the skinny rings are going around a much larger circle!

These are all points I'm trying to balance. If I cut down a tree, i will use it. I'd rather not cut down a tree. The lot I have in mind (and incidentally, all lots i can afford) are all young forest with no clearings. So my choice is to cut down some trees or don't build a house at all. I'm in the southeast US.  If I want to grow anything, i also need to cut down some trees to get a southern exposure. I plan to do that at the road to minimize the impact, or maybe there is already enough clear to support a garden.

I will walk the lot again and see if there is any place far enough between big trees to dig and not do damage. My guess is no. So given those parameters, do you have any other suggestions that have less impact? Thanks for helping me think through it.

EDIT:
In a related question, does it damage trees to build a dome over forest floor between trees without digging a basement?

Hi Ben.  I have to disagree with much of what you are saying, even though I think the gist of what you are saying has some potential validity.  Taking down trees is a big deal, and a person does need to consider all the ramifications of what that entails.

“overaged trees are mostly dead and grow slower, just look at how the rings get skinnier as they go out!” This logger fallacy that was used to validate cutting down our greatest forests is just a demonstration of geometric illiteracy, as the skinny rings are going around a much larger circle!  

I do agree that there is indeed a logger myth out there that considers old wood to be decadent, but your arguments to that effect are not accurate in my thinking.  Not because I'm an old logger who has cut a lot of trees down for huge lumber mills, I'm not an old logger, and although I just got a small mill, I haven't used it yet.  But I will.  I have, however cut down a lot of trees for firewood in my 48 years, and as a tree planter, and as a kid growing up in serious logging country, I've seen a lot of stumps.  Growth rings are, indeed, thicker when the tree grows faster or more in a given year, and thinner on slow growing years.  This is how tree scientists can tell if a tree had a bad year based on some small local event like another tree falling on it, or a larger climatic event like a volcanic eruption.  All the old trees will have a tighter growth ring at the year of a large climate event, as an example, and if they were downwind from the fallout from the volcanic ash, they might have a great boost in growth as a result of this nutrient gain, and thus have more growth/larger summer growth rings for a while in the few years following.  I've seen tree rings that are small for a while, then large for a while then small again.  This scenario might look like this in the reality of the tree: when it was a seedling/sapling it grew up in shade of other trees so it's growth rings were small, then one of the large shading trees nearby fell and so the sapling had some extra light so it grew faster and it's growth rings got further apart, then the already mature and strong branches of the other larger shading trees expanded into the gap in the canopy, closing most of the canopy to the younger tree before it got to full height, so it's growth rings got small again for a while... I've seen this, or other iterations of it many times.

Larger, older trees grow much more biomass per year,

 maybe.  It depends on a lot of things.

taking out a big tree is exponentially worse than taking out a small one

. A young tree the size of a coffee can is blasting a lot of carbon out of the air and building tons of soil, and the OP is talking about taking down a lot of these, OR a large tree. There is a difference to that and what you said, a big difference. While I do agree with your statements about the watershed, wildlife, et cetera, there are always going to be upsides and downsides to making a permacultural design or material choice and it comes down to context and site specifics; permaculture is never cut and dry black or white, it is infinite shading on infinite colors.

But Bill Mollison is pretty explicit that permaculture ethics do not validate cutting down established forest for doing permaculture

I believe Bill Mollison was speaking of taking down virgin forest.  This forest is likely second or third growth, maybe forth.  My guess without knowing any specifics of the species or site is that even in those large trees, the growth rings are mostly fat, not skinny.  If a tree falls in the forest, and nobody makes use of it, then it will likely rot and most of it's carbon will off gas to the atmosphere.  Not that rotting wood is not essential to the forest. It is.  I'm just making a point.  You can lock that carbon in much longer term storage by building with it or by making char or hugulkultur with it.  With huguls the carbon gets locked into the soil below grade in the bodies and wastes of fungi and microbial bacteria. With biochar the carbon is locked in for centuries.    

HI Rob Lineberger:

if i want to grow anything, i also need to cut down some trees to get a southern exposure. I plan to do that at the road to minimize the impact, or maybe there is already enough clear to support a garden.  

If you are going to make a house or use wood for anything in your life, some trees are gonna be a dying; better to be the guy doing the selecting, clearing, et cetera, and do it consciously then have some distant unknown clearcut (that was very likely made with lots of large trees falling for nothing so that the loggers can get at the choice mill trees, as well as tons of other collateral damage including burning slash piles, and massive eroding road networks) burdening your conscience.  I've lived in logging country most of my life, and have seen it all, even recently--like last week when I was huckleberry picking. You can always sequester a ton of carbon in your garden and forest soils with dead branches turned into biochar, to make up for the carbon loss of taking trees down, and you can always plant trees to make up for lost trees, and you can increase wildlife habitat on an acre with small ponds, bat boxes, owl and bird house, butterfly gardens, et cetera.  I would suggest, picking a place by the road if that is on the south side, as you seem to indicate.  Clear that area and put your house and garden as close to the road as bylaws or your need to be away from traffic allow.  I would clear more than you think is necessary, not because I think clearing a ton of trees is a great thing (Bill Mollison and Ben Z are on the right wavelength in this direction of thought), but because it really, really sucks when a tree falls on your house.  I've seen whole houses crushed to splinters by a large tree with canopy limbs.  I would do the biochar I mentioned and build deep biochar rich beds and hugulkulturs and plant a lot of fruit and nut trees around them in biochar pits beside the stumps of the trees you took down (the fruit tree will utilize the root network and bio community in the soil), and these trees will be in the place of the other trees that might have fallen on your house but because you can choose varieties that are shorter you will thus not have such a worry of them falling on your house.  These fruit trees can grow a long time, and you can plant more as they age.      

 

I don’t know much about this subject, but I was wondering if maybe the the variety of tree might be a consideration? Like if the big tree is a mature, productive pecan and the small trees are common, less useful varieties.

So I just spent all day cutting up an unproductive plum tree I took most of down this winter. While I am doing a Hail Mary graft on the base and or suckers with a preferred varietal, I should not judge cutting trees as a wipe sawdust off. I heat my house with wood. And if it matters, you all seem like good people to me.

I have done a ton of research on dendrology and forest biomass accumulation as a education ranger in Olympic and Redwood NP. I was told to stop by my boss because I got too wonky. Most of my knowledge is about NW species and the SE’ deciduous forest has important differences that I should not pretend to know about.  However, Robert, while of course your points about tree growth rates are useful in selective logging of second growth to maximize regrowth, It seems correlated that the largest biomass forests on earth like those I have lived in are also sequestering more carbon each year they grow intact (Noss’ book on Redwood Ecology), with trees that grow faster each year (on average) until their heartwood overtakes their sap wood and chokes the cambium. This limits the Redwood trunk lifespan to about 2500yrs because the heartwood increases at a faster exponential rate to the sapwood. At the same time, these Redwood trees are unique as conifers able to reiterate from any part of the plant like vines. Either way, it  is generally true of coniferous trees and forests of the west that they grow more aggregate biomass the older they are, and this makes sense if you think about the increase in photosynthetic surface area with a taller canopy with mixed heights of understory beneath. Of course a fourth year tree has greater potential to put on more relative biomass it’s fifth year, but that’s based on a much smaller base. It’s like a small economy growing at 12% a year, whereas a massive one like the US can’t sustain more than 2-3% but that’s still a lot more money accumulation overall than the developing country. A mature forest has more photosynthetic area to power carbon sequestration, sugar production and all the life processes and ecosystem benefits that result.

That being said, we have finally tipped towards more Redwood growth than is being cut down with selective logging in Redwood country’s second growth along the lines of points Robert made about how trees grow to fill gaps in the canopy from fallen trees. When thinning second growth and taking some larger trees for some short term economic benefit (their wood is also vastly better) but still considering longterm sustainability and profit, we take out a large percentage of small trees and a very small percentage of the larger trees, and none of the truly old growth (250yrs+) ideally.

Back to the original post, I think you will do the right thing for your situation given that you seem to care and seek advice. I would prioritize summer shade in your climate, but I am from the temperate rainforest and can’t take heat. In looking for your tree/trees to take out, you could remove one that shades prized trees that will be north of your house site and they would help make up for the carbon and habitat loss in the tree you take. Ultimately, A good house site and build can save many trees in the long run by reducing heating costs if you use wood, so that may be more important than any individual tree if it’s not really that  old. My neighbor cut down some trees here that were 24” thick and 18yrs old.

Thanks for helping me think through this.

The lot is 100 feet by 550 feet in a rectangle that runs almost directly South (high point) to North (low point).  I am in a city, so my guess is this is third or fourth growth.  Not positive.  Durham doesn't have much in the way of forest except for in preserves (Duke Forest, Ellerbee Creek watershed, etc.) As far as I can recall from what I saw the lot is a mix of 18"-24" loblolly pines, 24"-36" post oaks, and lots of 6" beech/oak/pine.  Probably a 2/3 mix pine and 1/3 hardwood.  Maybe half and half.

Shade is not going to be a problem on this lot.  Getting sun is.

There are 5-6 large fallen hardwoods where the bark has eroded and there is deeply grooved but seemingly solid wood.  I was thinking of trying to rescue the heart of these, if there is any hope of doing so.  If not, a hugel is in my future.  I've done one before so I'm confident in it.  Any wood I take will be used.  First for lumber if possible to help build house additions after the kiln drying.  Next for biochar.  If neither is suitable, into the hugel.

The first thing I plan to do when I buy the lot is put up bat houses. I'm also going to have at least one pond, probably 5000 gallons, for aquaponics and mosquito control. I guess it would be best to put that and the garden beds on the north side of the house, which will be far shorter than the trees behind it.

Thanks for the advice about removing and planting nut trees.  I definitely do not wat a tree falling on my house.  At the same time, it will be a dome with  two-foot-thick walls.  I'm hoping that gives me some measure of protection should a tree fall.  In any case, it is impossible to clear enough trees to prevent a collision: the lot is 100' wide and the trees are at least 50' high.  The lots to either side, I cannot clear. So I'm taking on risk no matter what.

Thanks again for your help!

I forgot to mention, that if you cut a large tree's roots on one side, it is a lot less stable, and is more likely, in a catastrophic wind storm to fall in the direction of the cut roots, or, if you are lucky, in the opposite direction because that weakened side tears out first. It's 50/50 depending on the directional force of the torus of the wind hitting it.  

Good answers above.

One thing that has not been mentioned however is the variety of the tree you are working around. Some handle tress better than others. For instance Eastern hemlock can have half its bark rubbed off and it will still grow, but rub the bark off on just one spot on a White Spruce and it will ultimately kill it. Oak are the same way, but they have delicate toes despite their giant demeanor, mess with their roots with an excavator and the entire tree will die. White Ash on the other hand, they have a tap root half way to the Indian Ocean and even then Satan is holding on to every root I swear. I would rather pull a huge Oak then a smaller Ash tree just because of how hard their stumps pull.


But as others have said, its better to make a safe homesite then regret it later. It takes a fair amount of space to move around while building. Trees grow back...

Hi Ben.  

However, Robert, while of course your points about tree growth rates are useful in selective logging of second growth to maximize regrowth,

 I think that my discussion on the topic was speaking of growth rings or growth rates, regardless of tree species, or forest systems, or management systems, that growth rings do not necessarily get smaller as a tree gets older.  This may be true of Redwoods, once they get to an extreme old age, but I'm speaking generally, of trees.  If a tree has growth rings that are countable, then the width of those rings directly correlate to how good of a season it had in terms of it's primary needs: sun, nutrients, moisture, and in terms of how these needs are effected by outside influence.  Anything that deprives a tree of any of these will hinder it's growth and thus create smaller growth rings, and any factor that increases these needed inputs will create greater growth, and this is correlated to larger growth rings.  A pair of tree rings is produced annualy.  The thinner one is produced during it's slower growing or in extreme cold climates, dormant period, whereas the fatter ring is produced during the intense growing season that peaks at the summer solstice.  Most of the forests that I have seen logged, where I planted trees (in the North Coast Temperate Rainforest), were old growth, or ancient (meaning, that unlike old growth that might have a catastrophic fire reset the majority of the system every 350-500 years, an ancient forest-usually as smaller groves within an old growth system- is so wet that even a lightning strike fire in the heart of summer is unlikely to burn more than that one tree, or perhaps it's closest neighbor, and these forests are dominated by extremely old trees 500-2000+) at the time of the clearcut.  I've seen time and again that the pattern of the rings are not uniform, that they vary significantly from year to year in some areas but can have some uniform patterns over the span of decades, and I have been led to believe that this is as a result of what the tree experienced in any given year.  Sometimes there is uniformity in it's pattern, which is a result of steady growth  (this is more likely in an even aged stand following a catastrophic event, but happens in all types of forest and correlates with a period (years, decades... ) of steady relatively even growth), but generally there will be some variations in the width of the rings due to multi aged effect of healthy old growth systems, and the effect of one tree on the next in addition to the correlations between climatic and external influences, such as drought, el nina type extreme wetness, damaging scars from impacts, fires, et cetera.  This is not simply to do with second growth forests, but is true (to my knowledge) across the board (pun intended).  I've seen way too many huge old growth sawn stumps to consider your initial statement about growth rings as valid.  These include, hemlock, balsam fir, Douglas Fir, Red Cedar, Sitka Spruce, Lodgepole pine, and many of these have diameters that a person can lay down on.  I do not have any experience with Redwoods, or their related forests, except to walk in a few of older stands in California and Oregon.  I'm glad to hear that they are tipping the balance in the direction of regeneration.  

I agree with you that the photosynthetic surface area of a large old tree is going to have a corresponding relationship of carbon sequestration and biological life in the soil.  The growth rate of smaller trees though is important, if there are many of them that would be removed.  That system that attaches to the network of those trees is very important to the forest system. The benefits to the ecosystem of keeping larger trees is definitely, though, a huge consideration.  I am a big fan of stewarding the large trees, and am a follower of Susan Simard's studies on Mother Trees.

   

I think that we, you and I, have a lot more similarities than differences in our thinking, and I value the way you have put so much thought and energy into learning about the forest you were working in.  I also envy the job that you had.  An education ranger sounds pretty awesome.  :)

Rob, I'm in a similar situation as you, as I bought an acre of Virginia Piedmont land 9 months ago, near DC.  It was almost entirely wooded, with beech, oak, tulip poplar, elm, small pines, and maple, with tons of thorns and other brush (max tree width at 3 ft).  I choose to remove most of the trees below a foot in width, using the brush to make habitat piles on my property borders.  Logs are used for terracing, raised beds, and firewood.  I still have too much shade for all the fruit/nut trees I'd like to plant, but I'm working on grass/cover crops between my existing trees.  I'm getting a lot of ferns and other plants growing between the trees, but I'm also trying to seed with clover, shade-tolerant grass, and some brassicas before big rain storms.  The soil is very rocky and rooty, but hopefully after a few years of stump rot it will be easier to work.  So far I haven't tried to grind the stumps or produce any biochar.

I should also note that I'm sandwiched between public woods and lots with a lot of trees... so I am REALLY sun-limited.  I could clearcut my entire yard and still have a decent amount of shade most months.  If I had a wooded acre surrounded by farming fields I might have been more conservative with tree removal.

I don't regret taking down the smaller trees, but there are one or two spots where the soil got a little baked.  So now I'm working more on cover crop plantings.  If I had to do it over again, I'd have removed the trees about 20% slower, taking the time for more mowing, leaf removal, and seed planting with hand tilling.  Unlike you, I have a house on the property, so tree removal is much harder.  Long-term, I'll keep all the oak trees, for wildlife food production.  No hugulkultur so far, way too much work with a shovel and pickaxe.

You could look into girdling some trees to create habitat and light.  I'd also remove the smaller evergreens, unless you need them for a windbreak or privacy.  For my land, I will probably plant some pine nut trees eventually for privacy on borders, but otherwise am staying with non-conifers.

If you want to be more conservative, you could also experiment with clearing/planting certain sections while keeping others untouched.  Just so you can see how the system reacts.

Roberto, your points remind me of a forest walk I used to lead called “Trees take us back in time” and how we can read the past through these “hieroglyphs written with sunbeams”. A Doug fir tells you it was open at the forest floor when it sprouted because it needed 6hrs light to survive. A western hemlock tells you no significan fire has come through during its life. A redwood tells you the temperature has been pretty tolerable for its lifetime. It’d be interesting to learn to read an eastern forest, which would be like Greek to me.

Very interesting thoughts going on here.  We bought 11 acres of heavily wooded land that is so heavily wooded that you can't walk more than 20 feet in any direction without having to walk around something.  We had no choice but to clear out enough trees to make a drive back to the house site.  We had no choice but to clear out enough trees to build a house and put in a septic tank and leach field.  Clearing the house site left an area just north of the house that will get enough sun to be able to garden.  That site won't be large enough to grow everything we might need, so we will grow full/part sun plants there and shade tolerant plants interspersed around the margins.

We want fruit trees.  There is an area on the south side of the property that was previously cleared.  Rather than cutting down a bunch of trees in the woods in order to plant fruit trees, we put fruit trees in the cleared area.  It just seemed more responsible to me.

If you are concerned about impact on surrounding trees, you might consider pier and beam construction rather than a slab.  Just my $.02.  And while I understand the desire to protect trees rather than cutting them down, unless you are building an earthbag home trees are being cut down somewhere to provide the lumber.

Some people are getting pretty philosophical/spiritual here.  I see an empty soap box and will jump up on it.  

Every form of life competes to survive.  There is more than 1 species for each ecological niche, and the species in the same niches tend to compete.  Simply by existing every species effects the environment and so makes the environment either better or worse for other species in the area.  Every form of life has species that we could call 'allies' or at least 'opportunistic followers' that tend to appear with it.  

Humans are in the same boat.  There is a tendency among some to think 'humans = bad, nature = good".  That's a little simplistic from my point of view.  We are part of nature, just like beavers and bedbugs.  Our ability to modify the environment is even greater than a beavers.  The problem has been that many people have spent about as much thought on our actions as most beavers probably do, which is 'focus on the immediate need'.  Beavers eventually do good, but eventually they often kill all the decent trees around their pond and have to move on.  Short term, they cause damage.  The beaver insists on his right to survive and make a home.  So should we.

Humans tend to be a boon to quick sprouting weed species as we burn or cut down trees.  We are hell on large predators.  This is not evil, this is just part of being human.  The evil comes from the fact that we have, at least temporarily, 'escaped' our environmental limits and the vast majority of our natural population limiters.  Every species, including ours, has a greater than replacement value reproduction rate.  I've seen spruce woods where there were just way to many young trees (about 1 coffee can width tree every couple of feet).  Eventually, they will thin out, naturally.  Cutting some will actually open things up and the surviving trees will grow better.

As I understand it, permaculture is not about making no impact on the land, it's about making a considered, planned impact on the land.  It's about modifying the ecosystem to serve humans better, without ignoring the rest of the ecosystem.  If you need a spot to put a home, maybe it's ok to cut a big tree.  It only takes one huge tree falling through your roof in the middle of a windstorm to ruin your whole week.  You should consider what you're doing though.  By cutting it down, you are removing a part of the environment that will take quite a while to replace.  I would be much more thoughtful about cutting down 1 hundred year old tree than 10 ten year old trees, mainly because of the time for replacement.  The question I would ask is, what are you going to put in it's place?  If you are planning on becoming a 'shepherd of the trees', as seems likely from your statements, then the grove will probably be in much better shape in twenty years than if you didn't take the tree.  (Living in inadequate housing for years can eventually lead a person to become disenthralled with a lifestyle or even a life partner, so housing matters).  A person, like any other lifeform, is entitled to try and find/make a decent den.