Reproduced from 2018 Growers Handbook: Nut Growers Society of Oregon, Washington & British Columbia – 103rd Annual Meeting, January 18 2018, pp85-89
A panel discussion with Jeff Newton, Lance Kirk and Rich Birkmeier. Moderated by Jeff Choate (OSU Extension)
Summary (HGA editor)
US orchardists have been experimenting with double density planting since the 1970s. Trees are planted more closely together than the intended final spacing, to increase per-hectare yields while the trees are still growing to mature size. The temporary trees are removed once the trees start to grow together.
The main benefit is improved cashflow during the early years of orchard establishment. Double-density planting also allows two different varieties to be planted and evaluated, and the less successful variety removed later.
Disadvantages are the effort involved in removing large trees, damage that can be caused to the permanent trees by the removal work, weak or distorted growth on the permanent trees if removal is delayed, and poor root strength on permanent trees which becomes more apparent after the temporary trees are removed.
Important note: Different varieties are more or less vigorous, and trees grow differently in different conditions. This article discusses vigorous US trees in their climate and soil – it isn’t an exact match for NZ cultivars in NZ conditions.
Article
Jeff Choate
To introduce the topic, for anyone who’s new to the hazelnut industry, double density is simply the concept of planting twice as many trees initially so that you can realize that extra harvest for the first few years. When the trees start to compete with one another the extra trees are taken out.
We have a lot of folks in the audience today who have taken advantage of this, perhaps opportunity, to plant double density, but maybe haven’t faced all the situations yet to come. A lot of folks may think that the costs are primarily just upfront with the trees and then in the year of removal. But, perhaps the panel will tell us otherwise.
Theoretically, you remove them somewhere around year ten, but that may vary with the soil type, the variety of tree, and also the care; whether you’re irrigating during that whole time or not.
For the first number of years, all the way up through at least year six, seven or eight, you are operating at a loss. You are spending money to get that orchard established. With double density, theoretically you will see a positive cash flow about two years sooner than traditional plantings. But, our panelists will tell us their experiences first-hand, and kind of translate the theory into reality.
I’d like to introduce our panelists. We have Jeff Newton, who’s worked with Christensen Farms since about 1982; so, for 35 years. They also operate Crimson West receiving station, with Willamette Hazelnut Growers, and also Hazelwood Orchards Nursery. Before that, Jeff worked in the vegetable seed industry.
Next, we have Lance Kirk, who grew up on a hop and hazelnut farm, and was a crop consultant for Wilbur Ellis, with 17 years of experience. Currently he farms about 300 acres of hazelnuts, ranging from about 85 years down to about a week and a half old. He also operates a receiving station for George Packing Company.
Third is Rich Birkemeier. He and his family have orchards and a hazelnut nursery near Canby. His father had a small orchard when Rich was born, so he’s pretty much been in the hazelnut industry all his life. His father was actually one of the first to plant double density back in the 70’s so he is going to provide a little bit of a historical perspective. And, Rich was privileged … I’m not sure of the use of that word here, but privileged to have the first large farm with Eastern Filbert Blight. So, that means that he’s seen the removal process, went through a complete removal of ‘Ennis’ and ‘Barcelona’ in the mid to late 80’s, and is now many years into a second removal, kind of going one tree at a time. So he has a tremendous amount of experience, and a passion for learning and helping others succeed.
Jeff Newton
Good morning. My history with double density started in 1982. Our first orchard was a double density. And, as I thought about this, I’ve never done a single density. Every planting, for all these years, has been double. There’s several reasons for double density, and one of the biggest ones, of course, is double production, to help offset these early years. Back when the prices were way cheaper, it was basically to help not lose as much money. It wasn’t “make money,” it was “not lose as much money.”
It used to be that you would plant one main variety. Nowadays we have a lot more choices of varieties so you can either use one or plant two varieties and put your decision of which one to keep off for eight years or when they start crowding each other. The costs vary. Early on you’re going to have the cost of two trees, two sawdusts, plastic and paint. At the end of the timeframe you will have the cost of removal. Some of your pruning cost will depend on if you’re going to keep that temporary tree or take it out. If you’re a ‘Jefferson’- ‘Jefferson’, then you mark them. You’ll know which is your temporary and you’ll do very minimal pruning on it through its lifetime.
After you’ve got the double densities, you’re committed. So it’s a matter of how to deal with them and when to take them out. The trick going into it is, have it in your mind that you need to take them out as they start crowding; well before they start really crowding each other.
A year or two before takeout time, I like to hedge the temporaries. Just fan them back. But, do it clear toa scaffold limb or at least a branching point. Don’t just cut the branches off because they’ll put on a big flush of brush, and you’ll be back in worse shape than you were before. You are taking half, a third or two-thirds of the tree off a year or two before removal. This spreads your brush load for removal out over time. I like to grind our brush now, as opposed to pushing and burning which is what we used to do.
I’ve used several different methods for removal. Clear back in time, I would cut limbs off and leave the crotch angles up and then try to lift and push the whole root ball out with a loader. You could only push maybe three or four stumps at a time out to the end of the field, and they wouldn’t burn because there was so much dirt in the roots. So, I ended up stacking them at the end of the orchard and they were there for years and years rotting down, and the squirrels loved living in them. It was a real problem. Since then, I’ve gone to cutting them off flush, either burning or grinding the brush out, and then I use a stump grinder. It only disturbs a small area, and it does not hurt the roots on your permanent trees at all. And, your remaining trees will respond very quickly.
I do mine on a three or four- year rotation. Trees on good soils will be starting to crowd each other the soonest. I’ve got some 20 year old interplants on poor soil that will never be taken out. So, you can spread the workload out on a particular field over two or three years’ time as they begin to push each other. Again, it’s very important not to let them push on each other. It will distort your permanent tree and cause you a lot of damage in the long-term.
Lance Kirk
Our first high-density was ‘Barcelona’ planted in the early 80’s. We started off that way, probably, because that’s what everyone was doing at the time. And, we quit after a few years. It just didn’t work for us. It was the labor part of it. Although, at that time, a lot of the trees we were getting were J-root. The trunks weren’t very big, but they started crowding on our ground by year eight. And the ‘Barcelona’ really wasn’t yielding that well at the time.
By year ten, we had to take them out. They were really affecting our trees. So, the tree never really got that big. We cut the trees off and then used a stump grinder, and that worked real well.
My next time trying the high density was in the mid-2000’s with the ‘Lewis’ variety planted 10 by 20 on well-drained high fertility soil with irrigation. We thought we were going to push these trees, get the best bang for the buck. And, I thought we’d try double density again. And, everything went well. You know, fertilizer, spray, everything made sense to us.
Year seven, the trees were starting to get pretty close. I remember thinking, “Oh boy, here we go again.” We are just starting to yield. I just feel like we’re starting to make headway with the crop. We started pruning. First we just took out some of the branches going towards the permanent tree. We pruned what we thought was fairly heavy. However we ended up not pruning heavy enough.
The next year we focused on pruning, and we had the trees marked so we knew which tree was coming out. We went in and started taking scaffolding. The scaffold that we left branched out and continued to affect that permanent tree. We drug our feet, didn’t really want to take the trees out and thought it was too soon.
I waited until year twelve, and then our permanent trees were distorted. So we thinned and ended up using the stump grinder. First we cut them all off at the ground, drug them out with four-wheelers and started a pile. Soon we realized, that pile was getting big in a hurry, and the full trees weren’t real easy to maneuver. We did about an acre of that and said we have to re-evaluate this. We had an outfit come out and grind them. So we cut them off and ground them. It worked pretty well but the trees were so tall they landed into the permanent tree, and we had to pull them, cut them and get them nice and tight. We spent a lot of time doing that. We are a small farm so we don’t have a lot of farm labor. Anyway we continued to do that and ended up with a ton of fire wood. I don’t know if there’s a market for it, if anyone’s interested.
This week I started using a little blade based on a three point of a tractor. I can go in and just cut the tree right off at ground level. I tried the grinder in tissue culture trees. I think a result of heading them and cutting back the scaffold made the roots grow out on the side. I mean they are huge. When we start to grind them all of a sudden we are chasing them halfway into the orchard, bringing them all up. So we gave up with the grinder on these tissue culture that are in sand. They are just growing a tremendous root mass.
What we’re doing is working; it is just slow and time consuming. But the worst part about it is what I did to the permanent tree. Once we took that extra tree out this last year, the permanent tree branches became all droopy. They elongated so much and the scaffold wasn’t strong enough because of the sunlight and lack of pruning the top, they got droopy. So I pruned out a bunch on the trees I’m keeping this year. It’s just been a vicious cycle.
My last orchard, planted last week is ‘Yamhill’ and single density, I’m looking for the long term. I don’t want to remove trees again. But at the same time I understand why people plant double density. There is a value in there but the hard part is making that decision to take them out and then start doing that. If you’re set up for it and you’ve been doing it 30 plus years it becomes old hat.
But when you are new growers and you’re getting into it, 8 years goes by quick. You have to start taking out a tree in 8 years and you’re just thinking, “I just started to get the yield.” That part is the struggle for me.
Question
Have you tried any of the large grinding equipment?
Lance
I’ve talked to a gentleman who does that and the concept is awesome. I think there is an opportunity for someone to come up with something that would work well. However the gentleman that I spoke to wants to chew up the dirt to get the density to break down the tree trunk. I didn’t want to go through and have 12 years of getting an orchard floor that is nice and firm and smooth and all of a sudden have a soft spot then a hard spot, just creating this wave in our orchard. So I’d basically have to rework the whole orchard. So I chickened out just because I didn’t want to tear up my ground. I definitely think that in this day and age there’s a lot of ideas out there.
Rich Birkemeier
I’m sitting here listening to these two guys and can relate to everything that’s been said and can agree with it. Yeah my dad was part of the generation that first planted close plantings. He started in ’65 with a ‘Barcelona’ planting. It was 20 by 20, which was kind of standard in those days but he figured with the cost per tree and that empty space he could make money by just coming back the next year and planting a tree in the temporary spot. We knew, going into that, our goal was to have a 20 by 20 orchard. We liked that for the space and we liked to work both directions. But the incentive to gain a little extra income in the meantime won out; without a lot of thought about how we were going to get that 20 by 20. It worked well, until about year 8 or 9.
This was on good soil and the trees started growing together. You could see fewer nuts in between trees, you could see trees start to deform and stretch to the sky. That’s when I found out we had some members of the family that couldn’t stand to cut out a perfectly healthy tree. So it started an inside family argument, what do we do now? We had this goal.
What happens is you plant close to gain income over the first 10 years say, and that’s an arbitrary number depending on the farm. But when you get there, all of a sudden your goal changes. It’s for next year’s crop, and the fear of losing half your crop because you took half the trees out causes us to procrastinate in doing anything and the trees get bigger. That went on for 2 or 3 years and it got worse and worse. We could see the permanent tree deforming.
Finally there was consensus that we needed to take them out. So I started by hedging the temporary trees, like Jeff did, and that didn’t work. The end of the first summer I had more wood regrowth than what I’d cut out. So my strategy changed, the next year instead of making a bunch of cuts to open up the tree and make space, I made two big cuts at the bottom of the scaffold to take out big limbs. That way the big growth went right up through the middle and didn’t affect the permanent tree. That was a lot of work and we didn’t really gain that much. We just cut off a lot of bearing wood, like we’d done before.
Finally we just disassembled those trees in the orchard, pushed them out, and burned it like brush. It was an awful project, the trees were way too big and we noticed that what we had left was kind of a fan shaped tree that didn’t recover as quickly as we expected when we opened it up to more light. Most of the root anchorage, the larger roots, went to the center of the row rather than growing together to the next tree. It’s as if the roots grew the same as the top of the tree. We could tell in a strong wind that they had been used to supporting each other to a certain extent. We took out half those stumps and there was a tendency for them to tip over in the row. It wasn’t a big problem but we could see that tendency. By the time I got through pushing all that out of an 80 acre orchard, and then grinding the stumps, I swore I’d never do this again.
Fast forward to the mid-’90’s. We were in a place where we had a pretty large block of EFB infected ‘Ennis’. Like Jeff mentioned we were one of the first in the Clackamas County to get it in a large commercial orchard. We thought we were actually doing quite well with the blight for a few years, but we had one year where the weather conditions were such that no matter what we did, it just exploded on the whole farm. Well, that put me into a panic, and we ended up planting a lot of ‘Lewis’ which was the best choice we had at the time. I planted high density because I was desperate to keep production. As they grew, we started having trouble with blight in the ‘Lewis’ and I remembered the problems of leaving the temporary tree. We got to the point about year eight, time to take them out, and I was determined to take out the trees a year earlier rather than a year later.
Very quickly I found when I went down the row, in so many cases, I would find a permanent tree that had a really fatal strike of blight and caving, and I’d cut her off, and then I’d come to temporary tree that was perfectly healthy. I didn’t get halfway down the first row, and I could see that this was not working. The strategy changed to where I would just go over everything every year and drag the sickest trees out, burn them and dig the stump with an excavator. If it was a temporary space, I wouldn’t replant it, and if it was a permanent space, I would plant with whatever variety I had at the time that was a good option.
What I didn’t realize until several years later was that when I eventually removed all the ‘Ennis’ trees, the pressure of blight on my farm dropped way off. The additional resistance of ‘Lewis’ was enough that they didn’t continue to decline as fast as I had projected them to. So, I had not been removing sick trees fast enough, and all of a sudden, I found I had temporary trees that were way too big. It became a huge project, and we had other things to do. We were replanting the permanent spaces, but they were not doing real well in many cases, because they did not have enough light.
Finally last year, we bit the bullet, took all the remaining temporary trees out, had them ground in place in the orchard, and saw our crop drop pretty dramatically. Fortunately, it was on a down year anyway. Since then we find that a disgusting percentage of the replacement trees are leaning. Their root structure is not strong enough to hold them up now that they’ve been opened up, and a lot of them ultimately will need to be replaced as well. We’re continuing to remove the permanent trees as they cave. We’re going to get much more aggressive now.
Lessons learned from that; young trees do not do well in a mature unless they have way more light than you think they need. That was one lesson. Another lesson is that while I was always afraid to leave a hole in my orchard by taking a tree out, I found that simply by removing sick trees, the yield did not drop. It’s as if all the trees that surround that one space benefit from having it gone. I’m not nearly as afraid to remove trees in a blighted orchard as I used to be.
Forward to 2003. When the ‘Barcelona’ got blight bad, we could see that it wasn’t going to be sustainable. I was desperate for something that at least I didn’t have to worry about spraying or pruning or replanting. We ended up planting 80 acres of ‘Yamhill’. It was on an experimental plan with a Memorandum of Understanding with the college. Frankly I didn’t care how they yielded, I just wanted something that I knew was going to be sustainable. Again, I planted 10 x 20, and again, we had some thoughts along the way.
If ever there was a variety that would yield itself to hedgerow management, maybe this is it. We had purchased a saw to help us with skirting them. They have a very horizontal low growth habit that needed a machine to manage. But as they got closer and closer together, we started seeing the same symptoms of deformed growth on both trees. We were going to have to do a lot of hand pruning of both or take every other one out. We decided to take every other one out, and we now have a 20 x 20 ‘Yamhill’ orchard.
We took them out in a timely enough way that it was easy. We cut them off all at once, and by the way, that’s a situation where you don’t want to get on the wrong row. It’s a horrible feeling, so now when we do that we take five gallon buckets and we set them next to the temporary tree all the way down, and as we cut trees, if we can’t look cross-ways and see a bucket, we don’t cut it. We fell them after harvest, let them dry down a bit right in the orchard so that they would burn, and then we found that we could hook two of them together with a chain and pull them out with a Gator really quick. We bucked them up at the headland and shoved them on a fire, and it went very quick and very slick.
We left most of the stumps to grow trees on. Where we took stumps out, it was mainly with an excavator. It takes a lot of space to handle a lot of stumps because you can’t burn a green stump with dirt on it in the wintertime; so we just piled them up in the back of the farm and burned them the next summer, and they burned like a candle. We’ve also got a stump grinder that we use a lot, and that works really well in a temporary space where you’re not going to replant. It doesn’t work so well where you’re going to replant a tree in that spot because you’ve got mostly sawdust as fill dirt. And you’ve got all those roots that are left just below the grinding spot.
So one of the biggest advantages I see today of a close-planted orchard, especially when we’re dealing with new varieties that we as growers really don’t know that much about; is the opportunity to plant two different varieties together and defer that decision on what you like best 10 years down the road. It’s a way of diversifying what we don’t know today with two varieties instead of just one. Unless you know everything, and then everything gets easier, you pick one variety and go for it.
Frankly, there are some questions I’ve thought about my own experiences that I always ask people when they’re considering, “Which way do I go on this?” I ask them, “Have you had a family discussion over who in your family can’t stand to cut out a perfectly healthy tree?” Another question is, “How big a work project do you really want to design into your life 10 years down the road?” because a lot of people that are older like to take that first 10 years’ income, but they really don’t want the work of doing what needs to be done down the road. “Do you have any other options as far as where to invest your money other than a tree?” That’s a little bigger view. If you’re growing an orchard on side hills, I’d recommend you not plant close plantings because harvesting equipment doesn’t work good on a side hill. If you run a strip, a bare strip up and down the hill, you’re going to have a lot of trouble with erosion, and it’s better to have the flexibility of a square planting from the beginning on a hillside all the way through.
I have a lot of people ask me, “Well, what happens if you just leave them, 10 x 20, you don’t take them out?” We actually have two or three acres of ‘Lewis’ that we did leave, just because it is in the way all the time and we haven’t gotten to it yet. We found that about year 20, they just hit a wall, and they just don’t grow well. The leaves don’t get any bigger than a golf ball, and they don’t yield well. Now the grass is starting to grow under them. They’re more prone to getting rot in the scaffold of the tree. They just go into a decline. It looks to me to be unrecoverable. So, this year, that’s all coming out. We’re going to start from scratch, which, really, is a nice way to do it.
Jeff
So are you going to plant double density?
Rich
Yeah, we’re going to plant double density.
Question
What happed to yield?
Rich
When we took every other tree out of the ‘Yamhill’ in a timely fashion, we were really surprised to find that we didn’t cut our yield in half. At best, it was a third. And, we had not done it all in one year, so we had part of the orchard to compare with where we had been. And, it was just the additional light from removing those trees that benefited the others that very first spring.
Question
How do you tell when they are too close?
Rich
That’s kind of a subjective, visual thing. But, I would say, when they start to touch, you’d better be thinking of taking them out the next year. Overcrowding is when you see fewer nuts per cluster and fewer clusters as well as when there is less production in the middle of the tree. They will start to stretch more in the top, and they will grow out towards the open alley. I’ve never cut out a tree myself when I didn’t think, “Hm. I should’ve done this last year.” You go from a long term perspective to one year at a time, and that procrastinating will just make a lot more work and be detrimental to your permanent trees.
Lance
My yield was only down 500 pounds from the prior year. And I still got a tree. And so, that wasn’t the shock. It’s just the damage that it was doing to my permanent tree long-term. And, when you take that one out, then you’re going to go “Wow.”
Rich
I think most people are expecting a pretty good crop this next year. And, it may not be the year to take everything out at once. But, if it’s a down year, you’re gambling with that. It’s hard to know.
Question
Does the variety make a difference?
Jeff Newton
It depends on your soil, the climate each year, and the variety. Lance: I have an ‘Ennis’ orchard, planted on 20 x 20 on heavier soil that is still doing well. We should have planted it higher density because it has just never grown that big. It is 35 years old now, is doing well. Rich: You reminded me of another scenario. Once in a while I talk with people who have planted a double density orchard and pushed them really hard with fertilizer and foliar feed, and water. And, they get to year eight, and they’re crowding, and they’re still in a vegetative state, and they got to that crowded point much sooner than they realized. So, it’s not for everybody. The other comment I’d make, in terms of varieties is, yes, ‘Barcelona’ is much more vigorous, as is ‘Ennis’. But, ‘Yamhill’ is spreading. I don’t consider it a smaller tree. I just consider it a short tree. ‘Jefferson’ and ‘Lewis’ have a wonderful growth habit, but they’re taller and they cast a bigger shadow. They crowd just as quickly as a spreading wide tree. Both of them will fill the space very quickly. Ours are now 15, and they’re touching in the 20-foot space.
We did see, when they are crowded, they will stretch for light like any other tree. But, when they’re stretching for light, they’re growing vegetatively for sun and they’re not producing with the sun. And, I think, once you see them start to stretch for light, that’s a signal that they should come out. Hazelnuts need lots of light. The only other time I saw a ‘Yamhill’ grow, is when my son had a fir tree in his yard that needed to come down. There was no place to fall it except on one tree in the edge of the orchard. So, we just dropped it right on that ‘Yamhill’ tree and broke it off so that all that was left was the stump. Three years later, it looked like the most beautiful tree in the orchard. It looked like a ‘Jefferson’.
Question
Were you irrigating during the entire time that you had the double density in there?
Jeff Newton
I am now, but years ago I wasn’t irrigating. I’d say, the irrigation is just going to change removal from 10 years down to8 years. But with all these new varieties, we don’t really know. There are no old trees. We don’t know what they’re going to look like as they get older.
Lance
My ‘Barcelona’s’ weren’t irrigated, but the ‘Lewis’ were. When Rich was talking about the elongation I thought back on mine. I was seeing that fora long period of time. So, I kept backing off on my fertilizer and my water, trying to stress them, so they would yield more. It’s easy to make these little mistakes trying to fix things when the problem is the trees are just too tight.
Question
We have heard a lot about this, but did you make money on your orchards?
Rich
Yes
Jeff Newton
You trade work for money. That’s what we do.
Lance
Don’t let it go too long.
Jeff Choate
Hopefully everyone heard at least one thing, maybe, they’d try to do, and maybe one or two they’d try not to do. Thank you very much to our panelists up here today.