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The effects of invasive pests and pathogens on strategies for forest diversification

View Article: PubMed Central - PubMed

ABSTRACT

Novel bioeconomic model assesses effect of tree disease on tree species mixtures.

Risk and damage of disease alters the optimal planting proportion of two species.

Diversifying reduces loss from disease even if resistant species benefit is small.

Optimal planting proportion sensitive to disease characteristics and economic loss.

Optimal planting proportion sensitive to disease characteristics and economic loss.

No MeSH data available.


Related in: MedlinePlus

The optimal planting strategy under the conditions of a mixture. The optimal planting strategy, δ*, for a risk neutral manager is given by Eq. (10) and plotted in a β − RP parameter space (the secondary infection rate vs. the timber value of species B relative to species A). The primary infection rate, ϵ, is altered between each column, and the probability of pathogen arrival, P is altered between each row. The grey scale (bottom right) shows δ*: a monoculture of species A when δ* = 0 (black), of species B when δ* = 1 (white) or a mixture of A and B when 0 < δ* < 1 (gradations of grey). The white line indicates the switch in planting strategy when only a monoculture is allowed (i.e. the border between the black and white parameter spaces in Fig. 2). Infected timber is worth nothing, ρ = 0, and all other parameter values are given in Table 1.
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fig0015: The optimal planting strategy under the conditions of a mixture. The optimal planting strategy, δ*, for a risk neutral manager is given by Eq. (10) and plotted in a β − RP parameter space (the secondary infection rate vs. the timber value of species B relative to species A). The primary infection rate, ϵ, is altered between each column, and the probability of pathogen arrival, P is altered between each row. The grey scale (bottom right) shows δ*: a monoculture of species A when δ* = 0 (black), of species B when δ* = 1 (white) or a mixture of A and B when 0 < δ* < 1 (gradations of grey). The white line indicates the switch in planting strategy when only a monoculture is allowed (i.e. the border between the black and white parameter spaces in Fig. 2). Infected timber is worth nothing, ρ = 0, and all other parameter values are given in Table 1.

Mentions: The optimal planting strategy, δ*, is plotted in Fig. 3 against the secondary infection rate, β, and the timber value of species B relative to that of species A, RP, when infected timber is worth nothing ρ = 0. When the pathogen arrives late in the rotation (small primary infection rate, ϵ, left-hand column in Fig. 3), it will always be optimal to have planted a proportion of species A, and for a large region of the parameter space it is optimal to have planted a mixture. A lower probability of pathogen arrival increases the region of the parameter space where it is optimal to plant only species A (δ* = 0, black). As the primary infection rate increases (center and right-hand columns of Fig. 3), the region in the parameter space where it is optimal to plant species A (either as a monoculture or in a mixture) decreases, and a region where it is optimal to plant a monoculture of species B emerges (δ* = 1,white). Again, this occurs because the loss due to disease is increased as the primary infection rate (and/or the secondary infection rate) increases, whereas planting a higher proportion of species B reduces the overall loss.


The effects of invasive pests and pathogens on strategies for forest diversification
The optimal planting strategy under the conditions of a mixture. The optimal planting strategy, δ*, for a risk neutral manager is given by Eq. (10) and plotted in a β − RP parameter space (the secondary infection rate vs. the timber value of species B relative to species A). The primary infection rate, ϵ, is altered between each column, and the probability of pathogen arrival, P is altered between each row. The grey scale (bottom right) shows δ*: a monoculture of species A when δ* = 0 (black), of species B when δ* = 1 (white) or a mixture of A and B when 0 < δ* < 1 (gradations of grey). The white line indicates the switch in planting strategy when only a monoculture is allowed (i.e. the border between the black and white parameter spaces in Fig. 2). Infected timber is worth nothing, ρ = 0, and all other parameter values are given in Table 1.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384431&req=5

fig0015: The optimal planting strategy under the conditions of a mixture. The optimal planting strategy, δ*, for a risk neutral manager is given by Eq. (10) and plotted in a β − RP parameter space (the secondary infection rate vs. the timber value of species B relative to species A). The primary infection rate, ϵ, is altered between each column, and the probability of pathogen arrival, P is altered between each row. The grey scale (bottom right) shows δ*: a monoculture of species A when δ* = 0 (black), of species B when δ* = 1 (white) or a mixture of A and B when 0 < δ* < 1 (gradations of grey). The white line indicates the switch in planting strategy when only a monoculture is allowed (i.e. the border between the black and white parameter spaces in Fig. 2). Infected timber is worth nothing, ρ = 0, and all other parameter values are given in Table 1.
Mentions: The optimal planting strategy, δ*, is plotted in Fig. 3 against the secondary infection rate, β, and the timber value of species B relative to that of species A, RP, when infected timber is worth nothing ρ = 0. When the pathogen arrives late in the rotation (small primary infection rate, ϵ, left-hand column in Fig. 3), it will always be optimal to have planted a proportion of species A, and for a large region of the parameter space it is optimal to have planted a mixture. A lower probability of pathogen arrival increases the region of the parameter space where it is optimal to plant only species A (δ* = 0, black). As the primary infection rate increases (center and right-hand columns of Fig. 3), the region in the parameter space where it is optimal to plant species A (either as a monoculture or in a mixture) decreases, and a region where it is optimal to plant a monoculture of species B emerges (δ* = 1,white). Again, this occurs because the loss due to disease is increased as the primary infection rate (and/or the secondary infection rate) increases, whereas planting a higher proportion of species B reduces the overall loss.

View Article: PubMed Central - PubMed

ABSTRACT

Novel bioeconomic model assesses effect of tree disease on tree species mixtures.

Risk and damage of disease alters the optimal planting proportion of two species.

Diversifying reduces loss from disease even if resistant species benefit is small.

Optimal planting proportion sensitive to disease characteristics and economic loss.

Optimal planting proportion sensitive to disease characteristics and economic loss.

No MeSH data available.


Related in: MedlinePlus