Considerations about life time and graft density of future Scots pine seed orchards

1. Considerations about life time and graft density of future Scots pine seed orchards Dag Lindgren, Finnvid Prescher, Yousry El-Kassaby, Curt Almqvist, Ulfstand Wennström Poster presented 05-09-15

2. Seed Orchard Model • The issue: • Developing scientific framework for the establishment of advanced generations seed orchards • Application: • Use the model with data relevant to the Swedish 3rd cycle of Scots pine seed orchards • Method: • Utilize experience of production levels, gains, and costs • Intensive management with focus on: Tree density (400 and 600/ha)

3. Model Parameters: • Density • Orchard size • 10 million seeds annually over life time • Cone harvest time • 1st harvest at age 15 yrs (or earlier) • Final harvest (40 yrs or earlier) • Costs: • Establishment • Management • Seed crop production/harvest/processing • Benefits • Genetic quality of seeds • Value of the seeds • Quantity of seeds

4. Swedish Scots pine seed orchard costs (€)

6. Scenario: density 400/ha, harvest from 15 to 40 years 1- The establishment cost represents a small part of the total cost 2- Management cost covers the entire seed orchard life 3- Total seed production dependent cost has a high share, but it is revenue-driven 4- Seed from the lower crown cost contributes substantially less than from the upper crown.

7. 600 grafts/ha produce marginally more expensive seed than 400. If harvest start at 15 years, the cheapest seed is obtained with 400 grafts/hectare. The seed price depends only slightly on orchard’s life span between 35-50, but if it is younger, then the seed becomes more expensive. With cone collection starting at younger age, the seed orchard investment will be distributed among easily collected cone crops, thus reducing the cost of seed by about 5%. However, early crops are more vulnerable to pollen contamination.

8. What about genetics? The genetic value of the seed crop is expressed using the time lag between harvest and establishment. Thus a value is given for genetically updated seeds harvested at age 0. There is a penalty for each subsequent year depending on genetic progress. The seed value does not necessarily reflect actual income to the manager, but the value for the organization is also involved. Considering genetics makes early seed more valuable!

9. What about genetics of pollen contamination? Pollen contamination is considered unfavorable. Young orchards have more contamination than mature ones. A quantitative comparison is presented for a typical planned seed orchard with 20 tested clones with genetic gain 20%, with manageable maladaptation.Red values from Lindgren and Prescher (2005). The higher contamination in the young seed orchard caused a relative gain loss of 3%, for ages in between young and mature the loss was estimated by interpolation.

10. Planting densities • It seemed unfavorable (higher seed cost and less benefit) to plant less dense than 400 grafts/hectare. • Sweden has established several experimental seed orchards with 600 grafts/ha some decades old, experiences from them are accumulating. The experimental orchards are enriching our limited knowledge of these denser plating. The short observation period makes above 600 unpredictable. • 400 and 600/ha main alternatives.

11. Early cone collection (tolerating contamination) is able to raise “benefit” by about 10%. Profit is almost equal for 600 and 400. It is possible to increase profit by about 20% by ending the orchard life earlier. The advantage of a short orchard life span is higher if cone collection starts earlier.

12. Cost components compared for harvesting ages 15 - 40 and 8 – 25 Seed cost = 0.00515€ Seed cost = 0.00528€ The alternative with short life span seed orchards with early cone harvest gives only marginally more expensive seeds. Establishment cost increases while harvest cost for the higher cones decreases.

13. Main conclusions • 600 grafts/ha is not clearly preferable to 400! • It often appears worthwhile harvesting early and not waiting for pollen production! • It appears worthwhile to replace orchards faster than every two decades! • Therefore, it appears worthwhile to consider intensifying the Swedish third batch program (larger area, earlier establishment, earlier harvest, earlier phasing out old seed orchards) than currently planned!

14. Acknowledgements Among all we have discussed with we would like to mention Bengt Andersson, Jörgen Andersson, Nebi Bilir, Matti Haapanen, Kyu-Suk Kang, Johan Kroon, Ola Rosvall, Martin Werner and Seppo Ruotsalainen for their valuable comments in discussions preceding the development of the conceptual framework, help in estimation input values, and preparation of this poster.