Response of eldar (Pinus brutia var. eldarica) and brutia pine (P. brutia) to trickle irrigation in an arid land Christmas tree plantation

Arizona imports a far larger number of Christmas trees than it produces each year primarily because local tree farmers have not as yet found suitable species and cultural techniques for growing Christmas trees in Arizona's harsh climate. A relatively new technique which involves growing drought resistant conifers in irrigated plantations near urban centers was tested using the exotic species eldar (Pinus brutia var. eldarica) and brutia pine (P. brutia). After two and one half years of growth, eldar pine produced larger and better quality Christmas trees than three brutia provenances tested. These resultS. were statistically significant when mean multiple comparison tests were applied to the variables height and a Christmas tree quality index. Tree response to growing conditions on the plantation was quite variable. A few eldar pines were large and well formed enough to be marketable during the 1980 Christmas season. Most trees will require another growing season. However, some trees from each provenance tested were obviously stunted and may never produce marketable trees. Possible explanations for these results include a lack of mycorrhizal infections on stunted pines, a differential tree response to under- or overwatering, or local differences in soil fertility.hydrology collectio