Considerations about timing 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

Modified for seminar 05-12-15

Establishment of seed orchards is one of the most important

things on earth!

• Good seeds is the cradle for a good forest the coming century;

• The foundation for the future economy and ecology of Sweden;

• An operative spear head for the future;• The interface where progress of science and tree

breeding are converted to increased value of the Swedish forest.

Summary DagL Komi 2005(except this poster)

• Harvest in seed orchards should generally be initiated early in spite of the pollen contamination (Nilsson and Lindgren 2005).

• Unbalances among genomes should be used as well in long term breeding as in seed orchards. Linear deployment is generally a good approximation. The exact degree of unbalance is an act of art (Lindgren 2005).

• Seed orchards remain seed production up to old age. Trees in forests may produce many seeds under the right conditions (e.g. thinning). You do not see a high proportion of the cones. But variation in cone set can still be evaluated (Prescher et al 2005)

Conclusions of this presentation (Scots pine) Komi 2005

• A model for setting seed values as a function of their genetic value was developed (seed value is linearly related to the genetic value).

• The main cost of a seed orchard seed is the collection cost, that is cheaper if the seed orchard is younger.

• The establishment cost is not a major cost of seeds.• The first seeds are almost always profitable to harvest in spite of the

pollen contamination.• The prevailing view has been that a pine seed orchard should serve

to age 40 or longer. It would probably be wiser of forestry to replace them at age 30 if better material is available! The per seed cost increase is small.

• The right time to start discussion about establishing a new seed orchard is probably just a decade after the preceeding one was established.

• The establishment third batch of seed orchards could preferable be accelerated!

• Seed orchard designs with 400 or 600 grafts per hectare does not differ much in profitability in this model.

Seed Orchard Model• The issue:

– 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 to set parameters seed production levels, gains, and costs

• Model Parameters:• Density

– Main scenario 400 grafts per hectare at establishment• Orchard size

– Adjusted to produce 10 million seeds annually over life time

• Cone harvest time– 1st harvest at age 15 yrs is main scenario– Final harvest at 40 yrs ís main scenario

• Costs:– Establishment– Management (including land rent)– Seed crop production/harvest/processing

• Seed benefits (“virtual income”)– Genetic quality (contamination considered)– Quantity– Monetary value

• No interest (Ingen kalkylränta)

Swedish Scots pine seed orchard costs (€)

Establishment:Fixed for a seed orchard 15,000per hectare 5,000

per individual graft 25Annual management / hectare 500Per seed:

Harvest, low (< 3m) 0.001Harvest, high (> 3m) 0.004

Processing 0.001

Harvestable seeds/ha

0

200 000

400 000

600 000

800 000

1 000 000

1 200 000

1 400 000

1 600 000

0 10 20 30 40 50

160grafts/ha400grafts/ha1000grafts/haAge

Seed production per hectare is higher with higher graft density, in particular for the early crops!

0

200 000

400 000

600 000

800 000

1 000 000

1 200 000

1 400 000

1 600 000

5 15 25 35 45Plantagens ålder

Frö

per h

ekta

r

Tillgängliga för skördStandardScenario

Operativt tillgängliga fröproduktionens utveckling över tiden (400 ympar/hektar), (skärt enligt SkogForsk, bilden visar bara att vår prognos är medvetet gjord så

den liknar SkogForsks)

Scenario: density 400/ha, harvest from 15 to 40 years

1- The establishment cost represents a small share of the total cost

2- Management cost covers the entire seed orchard life

3- 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.

Cost components, main scenario

Establishment

Management

Harvest low cones

Harvest high cones

Seed extraction and processing

Harvest high cones

Establishment

Cost components for Scots pine orchard

seeds

The highest cost component is harvest of high cones!

Establishment is a rather moderate share of seed cost!

Management

Harvest low cones

Extraction, cleaning

600 grafts/ha produce marginally more expensive seed than 400 (in spite of that seed production per hectare is higher!).

If harvest starts 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 cost will be reduced by about 5%. However, early crops are more vulnerable to pollen contamination.

Cost per seed (€), harvest starts at age 15

0.000

0.001

0.002

0.003

0.004

0.005

0.006

0.007

25 30 35 40 45 50

Age at last harvest

400 grafts/ha 600 grafts/ha

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 densities above 600 unpredictable.

• 400 and 600/ha main alternatives.

Densities in existing Scots pine seed orchards (Kang et al 2001)

Country Grafts/hectare

Sweden 318

Finland 267

Cost per seed (€) as (harvest start at 15 and end at 40)

0.00500

0.00510

0.00520

0.00530

0.00540

0.00550

200 300 400 600 1 000

Grafts/hectare

If harvest start at 15 years, the cheapest seeds under the model are obtained with 400 grafts/hectare.

The cost per seed decreases 5% if cone harvest starts early. The investment in the seed orchard results in more seeds and they are at a low level and thus cheap to collect! But these cones will be more exposed to pollen contamination.

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 seeds more valuable!

Annual genetic progress (%) 0.3500The average time from establishment to harvest (years, main

scenario) 28.24

Value (€) of a seed from new seed orchard (age 0) 0.0150

Value (€) of 1% genetic gain 0.0005

Seed value (€, main scenario) = 0.015-0.035*28.24*0.0005 = 0.01006“Seed benefit” (€/seed) = value (0.01006) – production cost

(0.00503) = 0.00503

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.

Young MatureContamination 100% 50%“Genetic gain” 10% 15%Selfing – within graft 0% -1.6% - among ramets 0% -0.7%Reduction for low diversity -0.5% -1.1%Uncertain adaptation -2% -1%Net “gain” of crop 7.5% 10.6%

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.

"Benefit" (€/seed) as a function of orchard life time

0.0040

0.0045

0.0050

0.0055

0.0060

0.0065

0.0070

0 10 20 30 40 50Life time of seed orchard

Harvest from15, 400grafts/haHarvest from15, 600grafts/haHarvest from8, 400grafts/haHarvest from8, 600grafts/ha

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.

Cost components, main scenario

Establishment

Management

Harvest low cones

Harvest high cones

Seed extraction and processing

Cost components, high benefit scenario

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!

• It is beneficial to invest more on new seed orchards!

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.