Interest rate is the dominant variable for evaluation of a given afforestation project.

The costs of producing export logs by simple silviculture, and of two sawlog regimes, assuming competent standards of management, are high compared with current stumpages. If export log type regimes are used to produce pulpwood, costs to mill will be as high, or higher than those in Scandinavia and North America. Costs are reduced by rapid establishment, and by concentrating on high quality sites.

New Zealand management has to decide whether the extra cost of producing high quality pruned logs, with versatile end uses and which are unlikely to be produced overseas, is warranted, when compared with export log type regimes. Production thinning regimes are expensive and incur high risks. The direct, quality log regime plus grazing could provide a likely source of comparative advantage to New Zealand.

The economics of pruning rather than production thinning, emerge as the significant study.

On current returns, the internal rates of return of both the export and direct log regimes are over 10%; that of the production thinning regime is 6.66%.

Results of afforesting land of site index 95 with radiata pine are evaluated at interest rates of 7% to 12% in terms of export dollars earned per import dollar, and by weighting all overseas transactions by 10%. An export log, and two sawlog regimes-one direct, and the other requiring production thinningwere evaluated for ''normal" rates of afforestation and felling. At 7% interest rate optimistic results for the three regimes are 9.3, 13.1, and 6.9 export dollars earned per import dollar, if social costs of roading and accommodation are included; these rise to 10.3, 14.9, and 8.3 if social costs are excluded. Corresponding ' 'medium'' and ' 'pessimistic'' results for the direct, and the production thinning sawlog regimes are 11.0 and 5.0; and 12.5 and 6.1.

At 7% interest rate, imports comprise 17, 14 and 13% of total costs for the three regimes respectively. Logging and other vehicles are the highest overseas costs.

The effect of a 10% weighting raises the internal rates of return of the project by 0.5 to 0.75%.

Location affects results and further studies should include all steps until the export produce is loaded on ship.

Results continue to reinforce the marked superiority of the direct regime over one prescribing production thinning, and to demonstrate the economic attractiveness of the export log trade at current prices.

Results of afforesting land of site index 95 with radiata pine are evaluated at interest rates of 7% to 12% in terms of export dollars earned per import dollar, and by weighting all overseas transactions by 10%. An export log, and two sawlog regimes-one direct, and the other requiring production thinningwere evaluated for ''normal" rates of afforestation and felling. At 7% interest rate optimistic results for the three regimes are 9.3, 13.1, and 6.9 export dollars earned per import dollar, if social costs of roading and accommodation are included; these rise to 10.3, 14.9, and 8.3 if social costs are excluded. Corresponding ' 'medium'' and ' 'pessimistic'' results for the direct, and the production thinning sawlog regimes are 11.0 and 5.0; and 12.5 and 6.1.

At 7% interest rate, imports comprise 17, 14 and 13% of total costs for the three regimes respectively. Logging and other vehicles are the highest overseas costs.

The effect of a 10% weighting raises the internal rates of return of the project by 0.5 to 0.75%.

Location affects results and further studies should include all steps until the export produce is loaded on ship.

Results continue to reinforce the marked superiority of the direct regime over one prescribing production thinning, and to demonstrate the economic attractiveness of the export log trade at current prices.

The economics of radiata pine (Pinus radiata D. Don) afforestation on site index 95 are evaluated for a "normal" tempo of management of a regime prescribing a production thinning. One hundred and thirty of the initial 900 stems per acre (s.p.a.) are pruned in three lifts to 18 ft, stands being thinned to waste to 200 s.p.a. at 40 ft. Thinning to 80 s.p.a. at ca. 90 ft produces 2100 cu ft net per acre of pulpwood. The final crop is felled at ca. 136 ft, age 36 yr, the 23.5 in. diameter-at-breast-height (d.b.h.) trees producing 9440 cu ft per acre net on truck.

Values are based on mid-1967 levels and are charged from the mid-point of the year of origin. Interest rates of 3% to 12% are evaluated.

Net land expectation values (LEV) at 7% are -$5.7 when social items are included and $6.0 when they are excluded. Corresponding internal rates of return are 6.7% and 7.4%. The equivalent values for a direct (no production thinning) regime are $99 and $117, and 10.5% and 11.5% respectively. In comparison the production thinning regime needs the same labour; produces much the same total volume, but in poorer grades; incurs greater managerial and physical risks; delays most returns for a decade; and is fundamentally inefficient in timing the reduction of stand basal area.

An open ended pulp commitment can be met at increased profit by combination of pulpwood and direct regimes, in preference to production thinning.

Forest Service policy is to pursue those regimes prescribing production thinning.

The economics of radiata pine (Pinus radiata D. Don) at a normal rate of afforestation, for sawlog production are evaluated for scrub-covered land, of relatively easy topography. Site index is 95. The rotation of 26 yr produces 8248 cu ft net per acre. Silviculture reduces final crop stocking to 80 s.p.a. by 35 ft and pruning two 18 ft lengths concentrates production on high quality logs. The forested areas are grazed from age 3%.

are based on 1967 levels and are charged from the mid-point of the year of origin. Interest rates from 3% to 14% are evaluated.

Net land expectation values (excluding grazing returns) at 7% are $99 when social costs are included and $117 when they are excluded. Corresponding internal rates of return are 10.5% and 11.5%.

Comprehensive sensitivity analyses are made on effects of altering costs and returns. At interest rates up to 10% sawing is the greatest single cost, then logging. Total costs of five pruning lifts and two thinnings to waste exceed logging costs at interest rates above 8%%. Pulpwood returns are minor.

Timing of tending steps is critical, otherwise risks are low.

The concept of concentrating production on high quality stems (64% of the sawn outturn is of high quality timber) and grazing stands may alter the class of land available for forestry.

The 10 yr reduction in sawlog rotations would help close the forest sector target gaps in national development. The regime evaluates where one of New Zealand's comparative advantages lies-the rapid production of high quality logs.

Genetic, physiological and morphological aspects of using rooted cuttings of radiata pine (Pinus radiata D. Don) for plantation forestry are reviewed. Techniques for providing low-cost cuttings which root and grow well have been investigated both at Berkeley, USA, and at Canberra, Australia. Over the 7-8 yr of the studies, the training of trees as hedges arrested the normal decline in rooting percentage quality of roots, and growth potential of cuttings taken from ageing tree-form plants. The hedges soon yielded over 100 straight cuttings per square metre of hedge top per year. The method could be a practical means of providing cuttings for raising large numbers of select stock for plantation establishment.

From the results of bending tests of glued laminated planks of New Zealand Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and solid planks of both New Zealand and imported Douglas fir, a breaking load criterion of 1050 lbf (4.67 kN) under a standardised laboratory test procedure is proposed for scaffold planks of Special Class (NZSS 1426: NZSI 1965). A single cross-section size of 10 x 2 in. (254 x 51 mm) nominal is considered rational for all scaffold planks. Other suggestions for improving the current Standard relate to the allowable defect and wood quality requirements for solid planks of Douglas fir.

A manufacturing specification for laminated planks which passed the criterion in ' 'acceptance tests" is appended for the guidance of those considering alternatives to kahikatea (Podocarpus dacrydioides A. Rich.) and imported Douglas fir for Special Class planks, in terms of the Standard. Binding the ends of this class of plank is mandatory.

Information basic to mechanical stress grading of planks, an attractive alternative to visual grading, is also given.

A modification of the standard soil/block technique for assessing the natural durability of timber is described. One block was buried flush with the soil surface and another was set directly on top of it. Lower blocks attained a moisture content suitable for decay more rapidly than did the upper blocks. Except for Pinus radiata D. Don sapwood blocks decayed by brown rot fungi, all the lower blocks lost more weight than upper blocks. This was particularly noticeable when durable or moderately durable timber was tested against white rot fungi. Results from lower blocks showed a better correlation with field results than did those from upper blocks.

Normal records of growth and yield of eight unthinned permanent sample plots of radiata pine (Pinus radiata D. Don) were supplemented to provide direct estimates of total stem volume under bark from sectional measurements. Volume/basal area lines were used to assess standing volume at time of felling, and stand volume lines based on stand height and basal area per unit area were computed from these data and from similar data based on stem analysis, to estimate standing volume at different ages. These basic data are intended to provide a reliable record of how the first crops grew, so that productivity in second and successive crops tended in the same way may be compared. Thus, each permanent sample plot has been relocated in the naturally regenerated second rotation and their initial stockings have been reduced to the same level as in the first crop.

Radiata pine (Pinus radiata D. Don) and Douglas fir (Pseudotsuga menziesii (Mirb.) Franco.) seedlings were subjected to waterlogging periods of 1, 2, 4, 3, and 16 weeks. Phosphorus-32 uptake and succinic dehydrogenase activity of waterlogged mycorrhizas were measured and compared with non-waterlogged mycorrhizas. After 2 weeks of waterlogging Douglas fir mycorrhizas absorbed less ³²P than control mycorrhizas; radiata pine mycorrhizas were not significantly affected. Waterlogging periods of 4 to 16 weeks reduced ³²P uptake and succinic dehydrogenase activity in both species.

Twisting of branches and leaders in radiata pine (Pinus radiata D. Don) in Mangawhai Forest has been relieved by applications of copper. The growth distortion is accompanied by a flatter branch angle, needle tip burn, and needle fusion. Levels of copper in the foliage of deficient trees are less than ca. 3 ppm.

A study was carried out in 1970 to determine the differences in soil physical and chemical properties between two 0.04 hectare (ha) plots growing radiata pine (Pinus radiata D. Don) in Riverhead Forest; one plot received the equivalent of 2.5 tonnes of superphosphate per ha in 1952 and the other no treatment. During the period 1958-69 the basal area of trees per ha in the treated plot increased by 44.70 m² compared to an increase of only 4.52 m² in the control plot.

Analyses were made on soil samples taken from three depths in three profile pits in each plot. The water table depth in the treated area was generally 500 mm lower than that in the control area; there was a considerable improvement in the structure of the treated soil; and the aggregates from the topsoil of the treated profiles were found to be much more water stable than those from the untreated profiles. Associated with the improved structure was a decrease in bulk density (0.93 to 0.82 gm/cc) and an increase in the macroporosity (7.3% to 20.4%) in the topsoil of the treated area. The major changes in the soil physical properties were attributed to the effect of the growth response rather than to a direct fertiliser effect.

for phosphorus levels, there were only minor differences in chemical properties between the two plots; a small reduction in the pH of the treated topsoil (4.67 to 4.46), and an unaccountable increase in exchangeable sodium levels in the treated soil.

Abundant mycorrhizas were seen in the treated soil but virtually none in the untreated soil. Carry-over effects on the establishment and growth of second rotation crops are discussed.

Colletotrichum acutatum, Simmds. f.sp. pinea n.f. sp. has been shown to be the fungus associated with "terminal crook" disease of seedlings of Pinus radiata D. Don, P. contorta Dougl., P. elliottiI Engelm., and P. pinaster Ait. in New Zealand forest nurseries in Northland, Central Auckland, South Auckland- Bay of Plenty, and East Coast. It is shown also to be a primary pathogen in Lupinus arboreus L, and L. angustifofius L. Laboratory inoculation tests have shown that it is capable of infecting seedlings of Lathyrus odoratus L. and Vicia sativa L. and is a wound pathogen of ripe tomato fruits (Lycopersicon esculentum Mill.). Isolates obtained from naturally infected plants of Lathyrus odoratus and Lupinus arboreus did not infect seedlings of Pinus radiata.

A modified azo-dye reaction test for heartwood in Pinus species using a non-carcinogenic dye precursor para-amino-NN-dimethylaniline (PANDA) in place of benzidine or ortho-tolidine is described. Sensitivity and ease of differentiation of heartwood and sapwood are essentially similar to those of the ortho-tolidine reaction. The presence of boron and copper-chrome-arsenic preservatives does not adversely affect the test.

Small-scale trials showed that the time required for treating freshly sawn radiata pine (Pinus radiata D. Don) timber with boron could be reduced greatly by using a hot and cold bath followed by diffusion at elevated temperatures. Results obtained were close to theoretical predictions and with 100 x 50 mm timber, the total treatment time required was 7-9 days compared with a normal treatment time of about 60-80 days for timber treated by momentary immersion plus diffusion. Subsequent trials with a commercial prototype plant confirmed these results and demonstrated that accelerated diffusion had many technical and economic advantages over the momentary immersion process.

Profitability evaluation of non-normal afforestation by the budget method has the disadvantage that: only one time stream is investigated; it is difficult to maintain comparability between different site indexes; and work is laborious. Advantages are: results are easy to follow and directly applicable to current afforestation rates; the weaker points and significant variables are identified; and results are easily updated as costs and prices change.

The profitability of radiata pine (Pinus radiata D. Don) on three site indexes, whether assessed by internal rate of return (IRR), present net worth (or land expectation value (LEV)), benefit/cost ratio, cost of production per cu ft criteria, or export dollars earned per import dollar required, at interest rates of 3% to 14%, showed the same ranking. Site index 110 was the most, 95 the intermediate, and 80 the least profitable. The IRR on all sites exceeded 8%.

Risks could not be quantified, but the degree of marketing, biological, and physical risk increases with longer rotations. The faster tempo of work on the highest (110) site index incurs a higher management risk, and hence requires staff of better calibre.

The greater and earlier yields from high site qualities increase profits, and are particularly valuable to national forest strategy in filling target gaps.

While forest location greatly affects profit within one site index, the greater profit of 110 against 95 is outweighed only by a 60-mile closer proximity of the forest to the port. But more favourable forest location considerably increases the ratio of export dollars earned by the forest.

The relative costs of clearing heavy initial forest cover on different site qualities at different distances from the port, and of steeper country are indicated, and a means of finding effects of other significant variables on profitability is provided.

Profitability is high throughout and market prospects are good; the cost of prohibiting log exports can now be calculated.

Results of afforesting land of three site indices, 80, 95, and 110 with radiata pine (Pinus radiata D. Don) are evaluated at interest rates of 3% to 14% in terms of export dollars earned by sale of logs per import dollar. Customs duty is excluded.

At 7% interest rate, results for the three site indices are 8.2, 9.9, and 10.7 export dollars per import dollar, if social costs of roading and accommodation are included; these figures rise to 9.6, 11.2, and 11.9 respectively if social costs are excluded. At 7% interest rate imports comprise 15%, 16%, and 17% of total costs for site indices 80, 95, and 110 respectively. Logging is overwhelmingly the most important forest import-dollar cost, at interest rates up to 13% on all site indices.

Results are sensitive to yields and export prices.

Location affects results and further studies should be made on a free-at shipside and free-on-board basis.

The economics of radiata pine (Pinus radiata D. Don) afforestation for the export log trade are evaluated for scrub-covered country of easy topography of site index 110. Twenty thousand eight hundred net of the 25,000 acres gross are initially planted in 11 yr, felling begins in the 16th year, and yields fluctuate between 4 million and 10 million cu ft annually until normality is reached in year 47. The yield for the normal rotation of 20 yr is 8,235 cu ft per acre net of utilisation losses. Silviculture aims at producing two 39-ft logs to a 6-in small end diameter (s.e.d.) by planting at 10 x 7 ft, thinning (probably to waste) to 150 stems per acre (s.p.a.) at 35-ft top height, and clearfelling at 110 ft.

Interest rates from 3% to 14% are evaluated; 1967 costs are used.

At normality 108 men are employed, 64 of them on logging, giving an average production of 79,300 cu ft per man-year.

The proportions of major costs at 7% interest are: logging, 45%; administration, 16%; social, 14%; establishment, 11%; and tending, 7%.

A net price-on-truck of 20.8c per cu ft is obtained after allowing 8.8c for port handling and 8.7c for a single log haul of 89 miles.

Comprehensive sensitivity analyses are made on the effects of altering costs and returns; the most important effects (expressed for a 7% interest rate) are:

1. Differences in yield of 500 cu ft per acre alter land expectation values (LEV) by 16%.

2. Differences in realisations of le per cu ft alter LEV by 10%.

3. Break-even growing costs are 6.4c per cu ft on stump.

4. The effect of locating the forest 40 miles nearer the port increases LEV by 36%.

The net LEVs at 7% are $145 and $166 when social costs are included and excluded respectively. The corresponding rates of return are 13.3% and 15.7%.

Compared with results from site index 95, growing costs are 17% less; productivity per man increases by 3%, and volume production per acre is 13% higher.

The economics of radiata pine (Pinus radiata D. Don) afforestation for the export log trade are evaluated for easy to rolling scrubland of site index 80. Twenty thousand eight hundred net of the 25,000 acres are initially planted by year 13, felling begins in year 25, and yields fluctuate between 4 million and 8.4 million cu ft annually until formal normality is reached in year 58. The yield for the normal rotation of 29 yr is 8,235 cu ft per acre net of utilisation losses. Silviculture aims at producing two 39-ft logs to a 6 in. s.e.d. by planting at 10 x 7 ft, thinning (probably to waste) to 150 s.p.a. at 35-ft top height and clearfelling at 110 ft.

Interest rates from 3% to 14% are evaluated; 1967 costs are used.

Eighty-two men are employed at normality, 49 of them on logging, giving an average production of 72,000 cu ft per man per year.

The proportions of major costs to a loaded-on-truck basis at 7% interest are logging 32%, administration 24%, establishment 13%, tending 7%, and social 16%.

A net price-on-truck of 20.8c per cu ft is obtained after allowing 8.8c for port handling and 8.7c for a single log-haul of 89 miles.

sensitivity analyses are made on the effects of altering costs and returns, the most important effects (expressed for a 7% interest rate) being differences in yield of 500 cu ft per acre altering land expectation values (LEV) by 45%, differences in realisations of le per cu ft altering LEV by 23%, breakeven growing costs being 11.3c per cu ft on stump, and the effect of locating the forest 40 miles nearer the port increasing LEV by 74%. The net LEVs at 7% are $31 and $48 when social costs are included and excluded respectively. The corresponding internal rates of return are 8.5% and 9.6%.

Compared with results from site index 95, growing costs are 47% greater (at 7%); productivity per man decreases by 6.5%, and a 25% greater area would be required to obtain the same volume.

The economics of radiata pine (Pinus radiata D. Don) afforestation for the export log trade are evaluated for characteristic scrub-covered Taupo pumice land, of relatively easy topography. Site index is 95. Twenty thousand eight hundred acres net of the 25,000 acres gross are initially planted in 11 yr, felling begins in the 19th year, and major yields fluctuate between 4.5 and 9 million cu ft annually until formal normality is reached in the 51st year. The yield for the normal rotation of 23 yr is 8,235 cu ft per acre net. Silviculture aims at producing two 39-ft logs to a 6-in. small-end diameter top by planting at 10 x 7 ft, thinning (probably to waste) to 150 stems per acre at 35 ft top height, and clearfelling at 110 ft.

Costs are based on 1987 levels and are charged from the mid-point of the year of origin. Interest rates from 3% to 14% are evaluated.

Ninety-seven men are employed at normality, 59 of them on logging, giving an average production of 76,750 cu ft per man per year. The approximate proportion of costs to a loaded-on-truck basis at 7% interest are: logging 40%; administration 19%; establishment 11.5%; protection 8%; tending 7%; and social 15%. A net price-on-truck of 20.8c per cu ft is obtained after allowing 8.8c for port handling costs and 8.7c for a single log haul of 89 miles. Comprehensive sensitivity analyses are made on the effects of altering costs and returns; the most important effects (expressed at 7%) are:

1. Differences in yield of 500 cu ft per acre alter net land expectation values (LEV) by 18%.

2. Differences of le per cu ft in realisations alter LEV by 12.5%.

3. Break-even growing costs - excluding logging - are about 7.7c per cu ft on stump.

4. Locating the forest 40 miles nearer the port increases LEV by 42% to $135 per acre, and reduces haulage from 16.5 million to 9.3 million ton-miles annually.

Net LEVs at 7% are $95 when social costs are included and $115 when they are excluded. Corresponding internal rates of return are 11.2% and 12.8%.

The high accident rate in logging, the demand for a fit male labour force, and the volume of road traffic are the main non-financial costs. Non-financial benefits from protection and lack of pollution are considerable.

The actual area has been farmed since 1947 and dairy units are now being replaced by sheep farms. No large-scale afforestation for the log trade has been planned; nor is there other evidence that land use decisions, or investments, are being taken on economic grounds.