COMMODITY: FORESTRY

TITLE: Seedling planting density reduces loblolly pine plantation productivity

CONTACT: Terry R. Clason, Hill Farm Research Station (318)927-2578

TAKE HOME MESSAGE: High seedling planting density has a negative impact on the growth and development of loblolly pine plantations. This growth impact reduces the financial potential of loblolly pine plantations.

PROBLEM / TOPIC: Excessive pine tree density can reduce individual tree diameter and height growth which can significantly impact long-term plantation development. As a plantation approaches harvest age this growth loss can be expressed as reduced wood yields and lower value products. Thus, income can be reduced significantly.

ACTION: The Hill Farm Research Station established a study to determine the impact of planting density on loblolly pine plantation growth and yield. Planting densities evaluated included 6 ft x 8 ft (908 seedlings/acre), 8 ft x 8ft (680 seedlings/acre), and 10 ft x 10 ft (435 seedlings/acre). Growth impact of planting density was determined through age 29.

IMPACT: Long-term growth data showed that in unthinned loblolly pine plantations, planting densities exceeding 680 trees/acre (8 ft x 8 ft) reduced plantation wood yields. Growth of a 10 ft x 10 ft (435 trees/acre) plantation surpassed growth of 6 ft x 8 ft (908 trees/acre) and 8 ft by 8 ft plantations at ages 11 and 18 averaging 4 and 8 cords/acre (Figure 1). By age 29, wood yields were similar for the 10 ft x 10 ft and 8 ft x 8 ft plantations, which exceeded the 6 ft x 8 ft plantation by 9 cords/acre (Figure 1). However, sawtimber volume differed between the 10 ft x 10 ft and 8 ft x 8 ft plantations, averaging 7,000 and 2,500 board feet/acre, respectively. Thus, potential growth losses can be mediated by manipulating seedling arrangement and reducing planting density. Seedlings should be arranged to minimize tree damage during thinning operations and planting density should optimize individual tree growth between planting and the initial harvest. Using lower planting densities could,

1. Lower initial investment cost,

2. Increase harvest volume and income from an initial thinning, and

3. Enhance plantation value at final harvest.

Figure 1. Merchantable volume at ages 6, 11, 18, and 29 by planting density

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COMMODITY: FORESTRY

TITLE: Early commercial thinning benefits the productivity of loblolly pine plantations

CONTACT: Terry R. Clason, Hill Farm Research Station (318)927-2578

TAKE HOME MESSAGE: Reducing pine tree density during the sapling stage of plantation development optimizes final crop tree growth. Larger crop trees increase the potential value of the final harvest enhancing the financial potential of loblolly pine plantations.

PROBLEM / TOPIC: Pine plantation tree density can be manipulated to produce an array of wood products during a single production cycle. An early thinning can remove competing trees before a plantation stagnates and can provide an early income resource. If properly timed, a thinning can reduce the length of a production cycle improving the financial potential of a pine plantation.

ACTION: In an existing loblolly pine plantation the Hill Farm Research Station established a study to determine the impact of early thinning on planting density on long-term plantation growth and development. Half of two initial planting densities, 8 ft x 8 ft (680 seedlings/acre), and 10 ft x 10 ft (435 seedlings/acre), was thinned at age 11 to 100 trees/acre. Growth between the unthinned and thinned treatment plots was compared through age 29.

IMPACT: Growth data indicate that an age 11 thinning reduced total wood yields for both planting densities at age 29 (Figure 1). The greater growth reduction was detected in the thinned 8 ft x 8 ft treatments, yields were 10.5, 11.0, and 6.5 cords/acre less than the
8 ft x 8 ft, 10 ft x 10 ft, and thinned 10 ft x 10 ft treatments, respectively. However, wood product distribution varied among treatments, greater pulpwood yields were detected on the unthinned treatments, while greater sawtimber yield were detected on the thinned treatments (Figure 1). Sawtimber yield for the thinned treatment averaged 27 cords/acre (8,910 board feet), exceeding the unthinned treatment average yield by 7.7 cords/acre (4,170 board feet). At age 29, the thinned 10 ft x 10 ft treatment sawtimber yield was greater than the other treatments, averaging 10,910 board feet/acre. Thus, sawtimber production can be enhanced by early thinning. If properly applied, thinning harvests can

1. Provide early income, and

2. Enhance plantation value at final harvest.

Figure 1. Merchantable stand volume at age 29 with and without early thinning.

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COMMODITY: FORESTRY

TITLE: Intensive vegetation management enhances early loblolly pine plantation growth and development

CONTACT: Terry R. Clason, Hill Farm Research Station (318)927-2578

TAKE HOME MESSAGE: Managing unwanted vegetation can improve the early growth and development of loblolly pine plantations. Optimizing early plantation growth can shorten the production cycle, enhancing its financial potential.

PROBLEM / TOPIC:Competitive interference from unwanted vegetation is a dynamic certainty during early plantation development that can reduce long-term productivity. Although various management practices can be used to alter the level of unwanted vegetation, little attention has been given to the interactive nature of these practices during the seedling stage of plantation development.

ACTION: A study was established at the Hill Farm Research Station to evaluate the effectiveness of four vegetation management systems on seedling stage growth and development of loblolly pine plantations. Treatments included a standard, chemical site preparation planted at 680 tree/acre (STD); herbaceous weed suppression = STD + post- plant harbaceous weed suppression (HWS); precommercial thinning = STD + reduce pine seedlings density to 350 trees/acre at age (PCT); and intensive = STD + HWS + PCT (INT).

IMPACT: Herbaceous weed suppression (HWS and INT) increased age 15 wood yields by 6.2 cords/acre (Figure 1). HWS wood yields exceeded STD yields by 6.6 cords and INT yields exceeded PCT yields by 5.8 cords. Although precommercial thinning with and without herbaceous weed reduced age 15 wood yields by 2.4 cords, sawtimber production was increased by 6.2 cords (Figure 1). At age 15, INT sawtimber production was 24.9 cords/acre surpassing STD, HWS, and PCT yields by 11.6, 6.5, and 5.7 cords/acre, respectively. Thus, the level of unwanted vegetation can be reduced by combining timber management practices, improving growth and development of seedling stage loblolly pine plantations.
 

Figure 1. Merchantable volume at age 15 by  vegetation management system

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COMMODITY: FORESTRY

TITLE: Wildlife habitat enhancement improves the financial potential of maturing loblolly pine plantations

CONTACT: Terry R. Clason, Hill Farm Research Station (318)927-2578

TAKE HOME MESSAGE: A commitment to management can sustain the investment potential of a forest resource. Periodic timber removal without adequate management guidelines can affect ecological development by altering vegetative composition in favor of less desirable species. Therefore, timber management practices can be used to achieve investment goals by maintaining forests at an economic stage of ecological development.

PROBLEM / TOPIC: Many landowners perceive timber management as a cost prohibitive option. Low stumpage prices and a belief that short-term investment goals conflict with long-term management requirements spur this misconception.

ACTION: The Hill Farm Research Station established a study to evaluate using timber management practices to improve investment potential of small-tracts of non-industrial forest land. The research area was a 30-year-old, 240-acre mixed pine-hardwood forest. Nine, 20-acre treatment plots were established and inventory data were used to separate the nine plots into blocks of three plots. Subsequently, three management option treatments,1) No Thin, allow initial timber value to accrue with no management intervention; 2) Thin, provide periodic revenue from intermediate harvests; and 3) Thin & Release, provide periodic revenue from intermediate harvests and hunting lease income, were assigned randomly to one plot in each block. Intermediate harvests were completed on the Thin and Thin & Release treatments at ages 30 and 38. Wildlife habitat enhancement was initiated at age 32 with a hardwood suppression treatment and was continued with prescribed burns at ages 35, 38, 41, and 44. Growth and income data were collected for 15 years.

IMPACT: The first thinning removed 7.6 and 7.4 cords/acre from Thin and Thin & Release treatments (Table 1). Harvest yields at age 38 were 7.0 and 7.3 cords/acre for the respective treatments options. Treatment pulpwood volume was similar at 2.4 cords/acre, while sawtimber volume was 4.6 and 4.9 cords/acre (Table 1). Total stand wood yield for No Thin, Thin, and Thin & Release treatments was 28.4, 26.9, and 27.9 cords/acre with sawtimber totaling 17.3, 15.2 and 16.4 cords/acre (Table 1). No Thin treatment actual total revenue exceeded the Thin and Thin & Release by 382.70 and 255.75 dollars/acre (Table 2). If actual costs and revenues were accumulated during this 15-year period at a 5 % interest rate, then the Thin & Release net investment value (NIV) surpassed the No Thin and Thin by 169.00 and 4.00 dollars/acre, respectively (Figure 1).
 

Table 1. Harvest volume and product distribution by management treatment
Treatments	Total Volume	Pulpwood	Chip-N-Saw	Sawtimber
	-------------------------------Cords/Acre-----------------------------
	Age 30 Harvest
Thin	7.6	3.4	4.2	-------
Thin & Release	7.4	3.4	4.0	-------
	Age 38 Harvest
Thin	7.0	2.4	-------	4.6
Thin & Release	7.3	2.4	-------	4.9
	Final Harvest
No Thin	28.4	9.6	1.5	17.3
Thin	12.3	1.7	-------	10.6
Thin & Release	13.2	1.7	-------	11.5

Table 2. Actual treatment costs and revenues by item in dollars per acre
Item	Age	No Thin	Thin	Thin & Release
----------------------------Costs----------------------------------
Stand Value	30	533.00	553.42	545.20
Harvest Costs
First Thinning	30	-------	16.21	16.21
Second Thinning	38	-------	15.25	15.25
Final Harvest	45	15.27	15.27	15.27
Habitat Management
Stand Release	32	-------	-------	58.16
Prescribed Fire	35	-------	-------	4.20
Prescribed Fire	38	-------	-------	5.00
Prescribed Fire	41	-------	-------	7.63
Prescribed Fire	44	-------	-------	10.00
--------------------------Revenue------------------------------
Intermediate Harvests
First Thinning	30	-------	248.62	239.76
Second Thinning	38	-------	327.73	344.50
Hunting Lease	31-45	-------	-------	75.00
Final Harvest	45	2,003.19	1,044.14	1,088.18

 

Figure 1. 15-year treatment investment comparison at a 5 % interest rate

 

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 Revised: September 22, 2000