Transcript Considerations of harvest time and graft density of future

Considerations about timing
and graft density of future
Scots pine seed orchards
Dag Lindgren, Finnvid Prescher, Yousry ElKassaby, 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
15,000
per hectare
5,000
per individual graft
25
Annual management / hectare
500
Per seed:
Harvest, low (< 3m)
0.001
Harvest, high (> 3m)
0.004
Processing
0.001
Harvestable seeds/ha
1 600 000
1 400 000
1 200 000
1 000 000
160
grafts/ha
400
grafts/ha
1000
grafts/ha
800 000
600 000
400 000
200 000
Age
0
0
10
20
30
40
50
Seed production per hectare is higher with higher graft density, in
particular for the early crops!
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)
1 600 000
1 400 000
Frö per hektar
1 200 000
1 000 000
800 000
600 000
Tillgängliga för skörd
400 000
StandardScenario
200 000
0
5
15
25
35
Plantagens ålder
45
Scenario: density 400/ha, harvest from 15 to 40 years
Cost components, main
scenario
1- The establishment
cost represents a small
share of the total cost
2- Management cost
covers the entire seed
orchard life
Establishment
3- Seed production
dependent cost has a
high share, but it is
revenue-driven
Management
Harvest low cones
Harvest high cones
Seed extraction and processing
4- Seed from the lower
crown cost contributes
substantially less than
from the upper crown.
Cost components for
Scots pine orchard
seeds
Establishment
Extraction,
cleaning
Management
Harvest low
cones
Harvest high cones
The highest cost
component is harvest of
high cones!
Establishment is a rather
moderate share of seed
cost!
Cost per seed (€), harvest starts at age 15
400 grafts/ha
0.007
600 grafts/ha
0.006
0.005
0.004
0.003
0.002
0.001
0.000
25
30
35
40
45
50
Age at last harvest
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.
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)
0.00550
0.00540
0.00530
0.00520
0.00510
0.00500
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 (%)
0.3500
The 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.
Contamination
“Genetic gain”
Selfing – within graft
- among ramets
Reduction for low diversity
Uncertain adaptation
Net “gain” of crop
Young
100%
10%
0%
0%
-0.5%
-2%
7.5%
Mature
50%
15%
-1.6%
-0.7%
-1.1%
-1%
10.6%
"Benefit" (€/seed) as a function of orchard life time
0.0070
Harvest from
15, 400
grafts/ha
Harvest from
15, 600
grafts/ha
Harvest from
8, 400
grafts/ha
Harvest from
8, 600
grafts/ha
0.0065
0.0060
0.0055
0.0050
0.0045
0.0040
0
10
20
30
40
50
Life time of seed orchard
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.
Cost components compared for harvesting ages
15 - 40 and 8 – 25
Seed cost = 0.00515€
Cost components, main
scenario
Seed cost = 0.00528€
Cost components, high benefit
scenario
Establishment
Management
Harvest low cones
Harvest high cones
Seed extraction and processing
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.
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.