We are interested in view on whether the different planting patterns in softwood plantations significantly affects form and wood property variation, and studies that examined them. For example if a stand is planted at 1111 sph, does the row x column pattern have any measured effect? Do stands planted on a 3 x 3 spacing differ noticeably and consistently from stands planted at 2 x 4.5?
In eucalyptus the spacing effect is not very pronounced. It affects some characteristics and not others (chemicals for example). A good study would be to verify what happens with the composition and dimensions of annual growth rings in relation to the initial growth until occupation of the soil with reduction of the volumetric increment.
Rectangular spacing: an economic benefit?
Abstract—Many loblolly pine (Pinus taeda L.) plantations are established at row spacings of 8 to 12 feet, but some companies are now using rows spaced 14 to 18 feet apart. Wide rows reduce establishment costs when sites are bedded, ripped, or machine planted. The cost of chemicals is also reduced when treatments are applied in bands along the row. A growth and yield program (Ptaeda2.1V) was used to predict volume losses from planting in 14- to 20-foot rows. Results suggest that when a thinning (to a constant basal area) is conducted at age 15, a rectangularity ratio of 2:1 reduces the amount of sawtimber predicted at age 23 by only 1 to 2 percent when compared to a square spacing. The cost savings associated with wider rows results in a slight increase in net present value (NPV). Field trials are needed to verify the biological effects of wide rows on volume growth and branch size of plantations established with less than 600 trees per acre.
This paper is available on ResearchGate. Rectangularity is an increasingly large issue in the southeastern US (e.g. Mississippi), given inflation and fuel costs, because in certain circumstances it can reduce regeneration/reforestation costs! And as you ask though, what impacts to yields and wood quality result from the reduced reforestation costs?
Harold Burkhart had several papers on this topic.
Curtis is the increase in MPV based on volume or on the value of timber as a function of quality(stiffness)? Increasingly we are trying to move to a system where volume and wood quality can be used to assess value.
Sorry, Geoffrey for the long delay. The benefits of rectangularity financially are not so much in terms of increased volume or wood quality (volume production may slightly decrease, depending on the rectangularity), but more so NPV is increased because of reduced reforestation costs. If you are bedding or subsoiling for site preparation, you should have fewer passes on a property as rectangularity increases, reducing fuel and labor costs, and especially if machine planting (but also hand planting), you will reduce costs because of fewer passes on the property (hence reduced fuel, labor) costs. If conducting banded (or say strips of herbicide), you will have fewer passes on the property, hence reduced chemical costs, fuel, labor. Basically boils down to fewer passes. With that said, rectangularity could be beneficial ecologically, less use of fuel, perhaps less erosion, less herbicide, should increase understory vegetation for a longer time relative to square plantings since you will have a wider "alley" between rows.
Unfortunately Harold Burkhart passed right around the time of my original post. Virginia Tech had several papers on this topic.
Attached are 3 papers that discuss or provide information about rectangurality on the growth and yield of loblolly pine plantations in the southeastern US.
Article Wood properties of young Douglas-fir in Southern Italy: Resu...
This paper discusses the impact of sylvicultural practises on the characteristics of douglas wood.
best regards
luigi
Thanks, Luigi. Here in the southeastern US, for say loblolly (and probably applies for slash), rectangular spacings of 3:1 (between row to within row) generally don't greatly impact yields. Some suggest no more than 2:1 though. Now wood quality, of course with rectangular spacing within row wood quality should improve in terms of self-pruning, and thus the question becomes between row. For instance, if you plant 16 feet by 6 feet (2:67:1), rather than say 10 feet by 10 feet, the tighter within row spacing should improve wood quality on those sides of the trees, but the wider 16 feet may hurt wood quality on the other sides of the trees. I have talked with wood products guys who feel like you could potentially rotate the log when sawing to minimze the between row knots.
How does Doug-fir grow in Italy. I have seen several papers mention the planting of Doug-fir in Italy. Is it faster growing than in the Pacific Northwest of the US? Age 19 thinning I think in the PNW of the US would be fairly early. I would think in general first thinnings (if conducted at all) would occur at age 30.
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