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Pinaceae (Pinus)



Pinus (ponderosa)


Pinaceae

Pine Family


Pinus

ponderosa



Laws.










Ponderosa pine

PINPON

Idaho

Ponderosa pine is the most widely distributed pine species in North America, ranging from southern British Columbia to central Mexico and from central Nebraska to the west coast from 200 to 3050 m (700 to 10,000 ft). The general distribution of Rocky Mountain ponderosa pine (var. scopulorum)is from the eastern slope of the northern Rocky Mountains in Montana east to central Nebraska and Kansas and south to eastern Nevada, western Texas, and Mexico. The distribution continues south from Texas into Coahuila, Tamaulipas, and San Luis Potos, Mexico. A broad zone of intergradation exists, however, between Rocky Mountain and Pacific ponderosa pines in southeastern Idaho and on both sides of the Continental Divide in Montana and Wyoming. In northern Idaho, it occurs from 610 to 2135 m (2,000 to 7,000 ft). Pacific ponderosa pine (var. ponderosa) ranges from southern British Columbia through the mountains of Washington, Oregon, and California.


plants

seed

Container (plug)

66 ml (4 cu. in) Ray Leach "Cone-tainers"

8 Months

Height = 15 cm Root-collar diameter = 2.8 to 3.5 mm Firm root plug

Ovulate cones mature in 2 years, and are upright, shiny nut-brown, ovoid to oblong, 8 to 15 cm (3 to 6 in) long and are borne singly or in groups, and bear winged seeds with a body length of 3 to 4 mm (0.11 to 0.15 in) and wing length of up to 15 mm (0.6 in). Trees start bearing cones at 6 to 16 years and can continue to produce seeds for up to 350 years. Good seed crops occur every 4 to 5 years in the Pacific Northwest.

Cones ripen in August and September in the interior and in September elsewhere. Cones can be collected by using ladders, hydraulic lifts, or by climbing trees, usually just before cones open. Cones should be dried quickly after harvest to prevent internal heating, mold development and rapid seed deterioration. After initial drying, cones can be temporarily stored in burlap bags, as long as adequate air circulation is provided around the sacks. Cones can be opened without the use of a kiln by spreading them on a tarp in a warm, well ventilated greenhouse or drying shed for 4 to 12 days. Pacific ponderosa pine cones are opened by placing them in a kiln at 49øC (120øF) for 2 hours whereas 74øC (165øF) for 2 hours is used for Rocky Mountain ponderosa pine. Seeds/kg = 22,000 to 34,000 10,000 to 15,000 seeds/lb) for Rocky Mountain ponderosa pine. Seeds are dried to 7% seed moisture content prior to freezer storage.

We bleach treat seeds prior to stratification. Seeds are placed into fine mesh bags and soaked in a 40% bleach solution (2 parts laundry bleach [5.25% sodium hypochlorite] to 3 parts tap water) for 10 minutes with hand agitation. Agitation is important to ensure complete sterilization. Seeds are thoroughly rinsed to remove all bleach residue and soaked in running tap water for 48 hours to ensure imbibition. Mesh bags are placed into plastic bags and seeds are stratified (cold, moist) for 60 days at 1 to 2øC (33 to 36øF). After stratification, seeds are soaked 24 hours in running tap water. Based on cumulative germination at 14 days in a germination test, the total amount of seeds needed for the crop is determined to ensure 90% to 95% of the cells have at least one seedling.

Seedlings are grown in 2 fully-controlled greenhouses. Photoperiod is extended by 300 watt incandescent lamps (15 min on/off cycles) at an intensity of 500 lux. Irrigation is applied by an overhead traveling boom system, with nozzles spaced every 40 cm. Fertilizers are injected into irrigation water with a 1:100 injector. Containers are filled with a 1:1 (v:v) Sphagnum peat moss and vermiculite medium having a pH of 4.2. Seeds are sown in late March and are immediately covered with a shallow layer of white grit or Forestry sand (6 mm deep) and immediately irrigated (acidified to a pH around 6.0) until the medium is saturated. Using a medium with low pH, irrigating with acidified water, using grit to allow air circulation around the root collar, keeping relative humidity low, and using underbench air circulation and heating reduces damping-off disease. Day-time greenhouse temperatures are maintained at 24 to 27øC (75 to 80øF), and night-time temperatures are maintained at 18øC (65øF).

Once seedcoats begin to fall off germinating seedlings, seedlings are thinned to 1 seedling per container. Photoperiod lights remain activated. Nutrients are supplied about twice a week. During the establishment phase (6 to 8 weeks), seedlings are fertilized with Peters Professional Conifer Starter (7N:40P2O5:17K2O; The Scotts Company, Marysville, Ohio) and CAN-17 (liquid ammonium calcium nitrate [17N]) to supply 65 and 23 ppm N, respectively, along with micronutrients (Fe, B, MgSO4). Phosphoric acid is used to keep pH of irrigation water around 6.0. Seedlings are irrigated when blocks weigh 80% to 85% of saturated weight. At the end of week 6, medium is leached with irrigation water to remove salt build-up. Day greenhouse temperatures are maintained at 24 to 27øC (75 to 80øF) and night temperatures around 18øC (65øF).

6 weeks

During the active growth phase, photoperiod control is continued. Nutrients are supplied about twice a week using Peters Professional Conifer Grower (20N:7P2O5:19K2O; The Scotts Company, Marysville, Ohio) and calcium nitrate (15.5:0:0:10) to supply 60 and 23 ppm N, respectively, along with micros (Fe, B, MgSO4). Containers are irrigated when blocks weigh 80% to 85% of saturated weight, but this is slowly decreased so that by the time growers wish to initiate buds, containers are irrigated at about 70% saturated weight. When seedling heights reach 11 cm (4.3 in) tall, medium is leached with copious amounts of irrigation water. Medium is then allowed to dry down until it is just barely moist.

5 weeks

During bud initiation, micronutrients (Fe, B, MgSO4) are supplied every irrigation, but N is only supplied every other irrigation using CAN-17 at 40 ppm N. Photoperiodic lighting is discontinued. Once buds are present (3 to 4 weeks after initiation), Peters Professional Conifer Finisher (4N:25P2O5:35K2O; The Scotts Company, Marysville, Ohio) and CAN-17 are applied to supply 12 and 81 ppm N, respectively, along with micros (Fe, B, MgSO4). We have had sucess using Peters Foliar Fertilizer (27N:15P2O5:12K2O) to improve root-collar diameter. Foliar fertilizer allows nutrient addition without extra irrigation. Also, it improves seedling N concentration and color. Phosphoric acid is used to keep irrigation water pH around 6.0. Temperatures are allowed to go to ambient, but preferably under 27øC (80øF) during the day. However, minimum greenhouse temperature allowed is -2øC (28øF). Seedlings are ready to be packed in January. From mid-September until pack-out, day temperatures are kept cool as possible and we prevent night temperatures from dropping below -2øC (28øF). Seedlings are hardened for 18 to 22 weeks.

22 weeks

Seedlings are extracted for storage in late November through December. Seedlings are well-watered before removal but foliage should be dry before packing. Seedlings are placed within plastic bags inside waxed boxes or plastic tubs and stored at 0.5øC (33 to 34øF). Seedlings are monitored for storage mold problems. Storage molds can be reduced by packing disease-free stock, storing them for the shortest possible duration, inspecting the crop for on-set of mold, shipping seedlings with minor mold occurrence first, and keeping temperatures below freezing.

4 to 5 months


Between crops, containers should be sterilized. We submerge Ray Leach "Cone-tainers" in hot water (75 to 85øC [167 to 185øF]) for 15 to 30 seconds to remove pathogens.

This protocol was originally developed in the mid-1980s when David L. Wenny was Director of the nursery and published as Idaho Forest, Wildlife and Range Experiment Station Bulletin 43.


Dumroese RK, James RL. 2005. Root diseases in bareroot and container nurseries of the Pacific Northwest: epidemiology, management, and effects on outplanting performance. New Forests 30:185-202.

Dumroese RK, Wenny DL. 1997. Fertilizer regimes for container-grown conifers of the Intermountain West. In: Haase DL, Rose R, coordinators and editors. Symposium proceedings, forest seedling nutrition from the nursery to the field; 1997 Oct 28-29; Corvallis, OR. Corvallis (OR): Oregon State University, Nursery Technology Cooperative. p 17-26.

Dumroese RK, James RL, Wenny DL. 2002. Hot water and copper coatings in reused containers decrease inoculum of Fusarium and Cylindrocarpon and increase Douglas-fir seedling growth. HortScience 37:943-947.

Montville ME, Wenny DL, Dumroese RK. 1996. Impact of foliar fertilization on container-grown ponderosa pine seedling viability. Western Journal of Applied Forestry 11:114-119.

Wenny DL, Dumroese RK. 1987. A growing regime for containerized ponderosa pine seedlings. Moscow (ID): University of Idaho, Idaho Forest, Wildlife and Range Experiment Station. Bulletin 43. 9 p.

Wenny DL, Dumroese RK. 1987. Germination of conifer seeds surface sterilized with bleach. Tree Planters' Notes 38(3):18-21.


Wenny, David L; Dumroese, Kasten. 2009. Propagation protocol for production of Container (plug) Pinus ponderosa Laws. plants 66 ml (4 cu. in) Ray Leach "Cone-tainers"; USDA Forest Service, Southern Research Station Moscow, Idaho. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/12/22). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.