Mounding Treatments Research Articles

Cultural Control of Giant Sugarcane Borer, Telchin licus (Lepidoptera: Castniidae), by Soil Mounding to Impede Adult Emergence

The giant sugarcane borer, Telchin licus (Drury) (Lepidoptera: Castniidae), also known as the banana stem borer, is an economically important pest of sugarcane in eastern Colombia. The presence of larval and pupal stages within stalks makes biological control of this pest difficult, and growers often resort to insecticide applications. Hilling up the soil around the base of plants, or soil mounding, is a cultural practice sometimes used to improve rooting in sugarcane. Because mature larvae cut holes in stalks close to ground level through which they can emerge as an adult, we hypothesized that soil mounding would impede adult emergence, and thus contribute to population reduction. Two experiments were conducted in fields with significant infestations of this pest in Puerto López, Meta, Colombia, during the seasons of adult emergence in this region (Apr–May and Oct–Nov). Manual mounding of soil to a height of 20 cm was tested in the first trial, and mechanized mounding of soil in the second, which also compared 2 mounding heights (10 and 20 cm). In both cases, 2 m row transects of plants were caged to collect emergent adults. Adult emergence was reduced up to 65% in all mounding treatments, whether manual or mechanical, and regardless of mounding height, demonstrating that this cultural practice could be a useful tactic for inclusion in an integrated management program for this pest. However, as with any other cultural practice in pest management, region-wide implementation likely would be required to impact local population densities, and efficacy will depend further on low levels of moth immigration from alternative host plants.

Toxicity, horizontal transfer, and physiological and behavioral effects of cycloxaprid against Solenopsis invicta (Hymenoptera: Formicidae).

The red imported fire ant, Solenopsis invicta Buren, is a significant urban, agricultural, and medical pest with a wide distribution in the world. Surface or mound treatment using contact insecticide is one of the main methods to control S. invicta. In the present study, cycloxaprid, a newly discovered neonicotinoid insecticide, was evaluated for S. invicta control and compared with two referent insecticides, imidacloprid and bifenthrin. Surfaces or sand treated with cycloxaprid, imidacloprid, or bifenthrin caused high mortality of S. invicta workers, and the action of cycloxaprid or imidacloprid was slower than bifenthrin. Like imidacloprid and bifenthrin, cycloxaprid can be horizontally transferred from corpses or live donor ants to recipient ants. In addition, cycloxaprid- or imidacloprid-treated surfaces significantly induced the activities of acetylcholinesterase (AChE) and detoxification enzymes; nevertheless, they had no significant effect on the foraging behaviors of S. invicta workers. Also, sand treated with cycloxaprid or imidacloprid did not negatively affect the digging activities of ants. Interestingly, S. invicta workers excavated significantly more sand containing 0.01 mg/kg cycloxaprid than untreated sand in the no-choice digging bioassays. In addition, extensive nesting activities (sand excavation and stacking) were observed in the flowerpots containing untreated sand or sand treated with cycloxaprid or imidacloprid. On the contrary, bifenthrin significantly reduced the foraging, digging, and nesting activities of S. invicta workers. Cycloxaprid is a slow-acting and nonrepellent insecticide against S. invicta workers, and its contact and horizontal toxicities are slightly higher than imidacloprid. © 2022 Society of Chemical Industry.

Long-term growth response of Norway spruce in different mounding and vegetation control treatments on fine-textured soils

Mechanical site preparation (MSP) is a common practice that precedes the planting of Norway spruce (Picea abies (L.) H. Karst.) in Nordic forests. Mounding has become the most used method in spruce planting in recent years. This study examined the effects of different mounding treatments (spot and ditch mounding, inversion, unprepared control with or without herbicide application) and a mechanical vegetation control (MVC) treatment done 3–4 years after planting on the post-planting growth of spruce container seedlings and their development to saplings during the first 11–13 years on two forest till soils in central Finland, one on flat terrain and other on a southwest slope. On these fine-textured soils the spot and ditch mounding methods favoured spruce saplings development. Inversion and unprepared plots showed weakest growth. On the site with flat terrain, 11 years post planting, spruce saplings were 78–144 cm (38–80%) taller and their breast height diameters were 11–13 mm (60–74%) thicker for ditch or spot mounding than for inversion or herbicide treatment. On the site with sloped terrain the differences were minor between the MSP treatments. MVC improved spruce height growth on sites which did not have intensive MSP, especially on control saplings planted on unprepared soil in herbicide and inversion treatments. On the flat terrain, MVC reduced the density of resprouts to be removed later in pre-commercial thinning. As a conclusion, spot or ditch mounding favoured the growth of spruce over inversion especially on flat terrain with fine-textured soil.

Intensive Mechanical Site Preparation to Establish Short Rotation Hybrid Poplar Plantations—A Case-Study in Québec, Canada

Because they generate more wood per area and time, short rotation plantations are likely to play an increasing role in meeting the global increase in the demand for wood fiber. To be successful, high-yield plantations require costly intensive silviculture regimes to ensure the survival and maximize yields. While hybrid poplar (Populus spp.) is frequently used in intensive, short rotation forestry, it is particularly sensitive to competition and resource levels. Mechanical site preparation is thus of great importance to create microsites that provide sufficient light levels and adequate soil water and nutrient availability. We conducted an experiment in Québec (Canada) to compare two intensive site preparation treatments commonly used to establish hybrid poplar. We compared the effects of double-blade site preparation (V-blade), mounding and a control on hybrid poplar growth and nutritional status four growing seasons after planting on recently harvested forested sites. We also evaluated the effects of site preparation and planted poplar on inorganic soil N. Our results confirmed general positive effects of site preparation on the early growth of hybrid poplar clones. After four growing seasons, survival was higher in the mounding treatment (99%) than in the V-blade (91%) and the control (48%). Saplings planted in the V-blade and in the mounding treatments had mean diameters that were respectively 91% and 155% larger than saplings planted in the control plots. Saplings were 68% taller in the mounding treatment than the control plots, but differences between the V-blade and controls were not significant. We did not detect significant effects of site preparation or the presence of planted hybrid poplar on soil inorganic N. Sapling foliar nutrient concentrations were not influenced by the site preparation treatments. Based on these results, mounding appears to be a good management approach to establish hybrid poplar plantations under the ecological conditions we have studied, as it is less likely to cause erosion because of the localized nature of the treatment. However, these environmental benefits need to be balanced against economic and social considerations.

A partial deciduous canopy, coupled with site preparation, produces excellent growth of planted white spruce

Survival and growth of planted white spruce (Picea glauca (Moench) Voss) were assessed at year 15 in boreal mixedwood stands of northern Alberta, Canada, in stands that were deciduous-dominated prior to logging or were conifer-dominated. Three overstory retention levels (0%, 50%, and 75% retention) and four site preparation treatments (mound, high speed mix, scalp, and no treatment) were evaluated. In deciduous-dominated stands, planted spruce performed best in the 50% retention; here, stem volume was at least double that of any other retention treatment after 15 years. In contrast, spruce had reduced growth in coniferous-dominated stands in both 50% and 75% retention treatments compared with the 0% retention. Survival of planted spruce was unaffected by level of retention, but survival was lower in coniferous-dominated stands than in deciduous-dominated stands; in the coniferous-dominated stands, survival was better with mounding and mixing and lowest with scalp treatments. All height variables tended to be greater in the mix and mound site preparation treatments. Finally, the best estimates of future total growth (regenerated spruce and deciduous combined) in the coniferous-dominated stands were in the clearcut treatment. In terms of regenerated spruce growth, the best estimates occurred in the deciduous-dominated – 50% retention stand planted with soil mixing–mounding treatments, where projected growth of spruce was comparable with that of open-grown and tended stands in Alberta’s boreal forests.

Effects of mounding and soil clay content on postplanting success of Norway spruce

Effective soil preparation by mounding is a common practice that precedes the outplanting of Norway spruce (Picea abies (L.) Karst.) in Finland, because of the improved survival and early growth of seedlings. On fine-grained soils, however, the postplanting performance of seedlings with mounding has been poorer than on coarser soils. The ecology of seedling growth and the effects of mounding on it on sorted fine-grained soils are still poorly known.This study examined the effects of mounding and soil clay content on the postplanting performance of Norway spruce container seedlings on soils ranging from medium-grained tills to fine-grained sorted clay soils in reforested sites in south-western Finland. First, regeneration results were inventoried on five plantations of differing soil texture. These reforestation sites had been mounded and planted with Norway spruce five to six years earlier through practical forest management. Secondly, mounding treatments (normal ditch mounding with a mound height of 15–25cm, ditch mounding with a lowered mound height of 5–10cm, spot mounding and unprepared treatment) were applied on five clearcut sites with different soil textures. These sites were mounded in the autumn and planted in the following spring, and the postplanting performance was measured after three growing seasons.The results showed that mounding decreases early postplanting seedling mortality and increases growth, thus promoting plantation establishment on forest soils with varying soil textures. The mounding method or mound height showed no clear difference in seedling growth in the studied soils and years. Early postplanting seedling height growth and survival (three years from planting) were slightly and root-collar diameter a bit better related to the soil clay content; the seedling attributes tended to be poorest on silty soils with a clay content of 20–30% (or silt and fine sand content of over 60%), compared with coarser or finer (clayey) soils. The results suggest that even effective soil preparation cannot fully alleviate all of the inherent disadvantageous effects of sorted silty soils on early postplanting and later growth; but corroborative research is still needed.

Field Evaluations of Broadcast and Individual Mound Treatment for Red Imported Fire Ant, Solenopsis invicta Buren, (Hymenoptera; Formicidae) Control in Virginia, USA

Field evaluations were conducted to determine efficacy, residual activity, and knockdown potential for fire ant control products. Broadcast granular products (Advion, 0.045% indoxacarb; and Top Choice Insecticide, 0.0143% fipronil) were individually evaluated, and compared with a combination of two products applied together, and with individual mound applications of Maxforce Fire Ant Killer Bait (1.0% hydramethylnon). After application, the greatest percent reduction (90 days) were observed in the Advion/Top Choice combination plots (100.0%), followed by Top Choice alone (96.4%). Advion and MaxForce produced significantly lower foraging reductions at 90 days (61.2% and 27.5% respectively). At the conclusion of the test (day 360), significantly fewer ants were collected in the Advion (777.7), Top Choice (972.8), and combination plots (596.2) than in the control plots (1257.8) ( df 13, F = 8.3, P 0.05). Overall, the efficacy and residual studies suggested that the Advion/Top Choice combination produced both the most rapid reduction in ant foraging and the longest lasting control (90%) at 300 days. When evaluating time to knockdown of foraging populations, the Advion/Top Choice combination also provided the most complete and rapid results by day 7, reducing foraging by 100%. While other products also performed well (75.6 - 95.9% reductions), both the MaxForce and Advion plots had significant increases in foraging at 30-90 days. Overall, foraging knockdown was the most complete in the Avion/Top Choice combination plots at 90 days.

Nesting of the Fire AntSolenopsis saevissima(Hymenoptera: Formicidae) in an Urban Environment

Ants of the genus Solenopsis are common in urban environments due to their abilities to explore resources and to establish nesting sites, which helps their proliferation and also increases the occurrence of encounters with people and severe stinging. We aimed to increase understanding of this species in urban areas, so this study attempted to answer these questions: Are certain seasons more amenable to the founding of new colonies? Does colony size vary among seasons? What sites are used by these colonies in an urban environment? Observations were carried out every 2 weeks from May 2011 to Apr 2012 in Juiz de Fora, Minas Gerais, southeastern Brazil. For each active colony the site and the dimensions of the nest were registered. We showed that colonies of Solenopsis saevissima (Smith, 1855) were present in urban areas during the entire yr, with the highest incidence in the wet season, and nesting sites were associated mainly with vegetation. Because the dry season (Apr–Aug) was the period that had the smallest number of active colonies, this period could be considered the most favorable for area-wide control operations, but an individual mound treatment approach in the dry season should be take into consideration the occurrence of cryptic mounds.

Does Prescribed Fire Facilitate Fire Ant Invasions in Coastal Prairies or Aid Management by Improving Mound Search Efforts?

Abstract We established a high-intensity prescribed-fire experiment in shrub-dominated coastal prairie to quantify (1) the proportion of Red Imported Fire Ant mounds that are likely to be missed by applicators of individual mound-based chemical treatments in prairie, based on the number of mounds found in unburned prairie compared to recently burned areas, and (2) to track changes in the densities of Red Imported Fire Ant and native Red Harvester Ant mounds in response to growing-season prescribed fires conducted during drought. First, our data suggest insecticide applicators are likely to miss 48% of Red Imported Fire Ant mounds when applying individual mound treatments in shrub-infested prairie. Second, fire treatments did not increase Red Imported Fire Ant or decrease Red Harvester Ant populations. Prescribed fire may therefore provide an advantageous management option for prairie managers that does not increase densities of Red Imported Fire Ants, and maintains mound densities of Red Harvester Ants, w...

Twenty year responses of white spruce to mechanical site preparation and early chemical release in the boreal region of northeastern British Columbia

The effects of six mechanical site preparation treatments, two stock-type treatments, and early chemical release on survival and growth of planted white spruce (Picea glauca (Moench) Voss) were studied in the BWBSmw1 biogeoclimatic zone of northeastern British Columbia. After 20 years, spruce height and diameter were larger in all mounding treatments than in the control. Early results suggested better spruce performance on large than small mounds, but after 20 years, growth was equally good on small mounds as on mounds with 20 cm mineral capping. Spruce planted on hinge positions in the Bräcke patch and blade scarification treatments did not survive or grow well. Early chemical release improved spruce growth equally as well as the mounding treatments. Twenty year spruce survival averaged 71% in the 14 and 20 cm mound treatments, 60% in the early chemical release treatment, and ≤35% in the Bräcke patch and blade scarification treatments. A large stock type was also planted in untreated ground and, after 20 years, had similar survival and growth as the standard stock type. Differences in survival had a large effect on basal area at age 20 years. Trend analysis showed that treatments diverged into two distinct groups with regard to spruce size during the 20 year span of the study.

Effects of site preparation treatments on early growth and survival of planted longleaf pine ( Pinus palustris Mill.) seedlings in North Carolina

We tested the effects of eight site preparation treatments on early growth and survival of container-grown longleaf pine ( Pinus palustris Mill.) seedlings. Treatments included an untreated check, six combinations of two initial vegetation control treatments (chopping or herbicide) with three planting site conditions (flat [no additional treatment], mounding, or bedding), and a more intense treatment consisting of chopping, herbicide, and bedding. All plots were prescribed burned after site preparation and before planting. Seedling survival was not significantly different among treatments at either 12 ( p = 0.768) or 20 ( p = 0.881) months after planting. Both bedding and mounding increased root collar diameter after 20 months when compared to flat treatments ( p ≤ 0.002). Between the vegetation control treatments, herbicides increased root collar diameter growth over chopping ( p = 0.002) while chopping did not significantly differ from the check. The most root collar growth occurred on the chopping/herbicide/bedding and herbicide/bedding treatments, with the least on the flat (check) and chopping/flat treatments. The percentage of seedlings in height growth 20 months after planting was higher on bedding and mounding treatments when compared to flat treatments ( p ≤ 0.003). Herbicide was also significantly better than chopping with respect to the percentage of seedlings in height growth ( p = 0.016). The treatments with the most seedlings in height growth were chopping/herbicide/bedding followed by herbicide/bedding and herbicide/mounding.

The economics of site preparation and the impacts of current forest policy: evidence from central British Columbia

A trend in forestry is to move away from intensive stand establishment practices in favor of prescriptions that are lighter on the land. This study examined the condition and projected yields of nine different site preparation treatments on two high-elevation sites in central British Columbia. Treatments included the following: raw planting (i.e., no site preparation); scalping; mounding; chemical site preparation; chemical brushing; and combinations of mounding and chemical treatments. All treatments were manually planted with 2+1 bare-root interior spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) seedlings. By age 15, trees growing on prepared sites had significantly greater survival, larger stem diameters, and taller tree heights than did trees that were raw planted as seedlings. Moreover, site preparation generally led to earlier and less costly compliance with mandatory reforestation requirements. Growth and yield simulations predicted raw-planted timber volumes that were just 33%–51% of the volumes in the most productive treatments. Financial returns varied as well. Site preparation typically resulted in larger land expectation values than that resulting from raw planting; however, the results were sensitive to rotation length and discount rate. Collectively, these results suggest that moderate investments in site preparation may lead to a more profitable allocation of regeneration resources and a greater future timber supply.

Root growth and nutrient uptake of Norway spruce container seedlings planted in mounded boreal forest soil

The effects of mounding on root and shoot growth and nutrient uptake in 1- and 2-year-old Norway spruce ( Picea abies (L.) Karst.) container seedlings were studied for 2 years after planting at a clear-cut forest site in Finland. Three different mounding treatments (spot mounding with and without mixing, and inverting) were compared with two unscarified treatments with or without a cardboard mulch. All of the mounding treatments that were used enhanced both the root and the shoot growth and also the nutrient uptake of the 1- and 2-year-old seedlings compared with the unscarified treatments. The foliar nitrogen concentration increased after planting, but the concentrations of other nutrients decreased. In particular, foliar boron decreased to a level of deficiency. The biomass growth of roots and shoots was greater in 2-year old than in 1-year-old seedlings. The results suggest that larger 2-year-old seedlings can utilize improved soil conditions after mounding slightly better than 1-year-old seedlings.

Effects of Mounding on Damage by the European Pine Weevil in Planted Norway Spruce Seedlings

Abstract The European pine weevil (Hylobius abietis L.) is not found in northern America so far but is the major pest in conifer reforestation in northern Europe. The effects of mounding on pine-weevil damage and growth in planted Norway spruce (Picea abies (L.) Karst.) seedlings were studied on two clearcut forest sites in Finland. Three different mounding treatments (spot mounding with or without mixing and inverting) were compared to three unscarified treatments with or without vegetation control (mulch or herbicide). Mounding significantly decreased pine-weevil damage, mortality, and growth losses of planted Norway spruce seedlings even if insecticide was used before planting. Seedling growth and survival were poorest with the heaviest feeding by the pine weevil. After the first growing season, the proportion of gnawed seedlings was higher on unscarified spots (76% gnawed), whereas seedlings on mounded spots had hardly any feeding (1%). Seedling mortality was lower on mounded (1%) than on unscarified spots, where it was higher in 1-year-old (27%) than 2-year-old seedlings (10%). After the second growing season, mortality and proportion of gnawed seedlings increased on both mounded and unscarified spots. The study indicates that mounding can provide an effective method of decreasing pine-weevil damage and improving plantation success.North. J. Appl. For. 22(3):154 –161.

Field Applications of Bait-FormulatedBeauveria bassianaAlginate Pellets for Biological Control of the Red Imported Fire Ant (Hymenoptera: Formicidae)

The red imported fire ant, Solenopsis invicta Buren, is an important pest in the southern United States, in part because few natural enemies exist. Beauveria bassiana is an entomopathogenic fungus that holds great promise as a biological control agent against S. invicta. In previous studies, B. bassiana was effective in laboratory trials, but field applications were less effective. In the current study, we compared the efficacy of different application methods of B. bassiana mycelia encapsulated in alginate pellets against S. invicta in heavily infested areas. Direct insertion of pellets into S. invicta mounds caused some reduction in activity rating. However, observations of ants removing pellets from mounds shortly after insertion led to the development of a bait system to encourage pellet retention in the mounds. Broadcast applications and individual mound treatments of B. bassiana alginate pellets coated with peanut oil reduced activity ratings of S. invicta populations.

Site Preparation for Establishing Interior Spruce in British Columbia: Trials at Upper Coalmine and Mackenzie

Abstract Two trials (“Upper Coalmine” and “Mackenzie”) were begun in the 1980s in the Prince George Forest Region, B.C., to evaluate a total of 13 site preparation treatments for establishing interior spruce (Picea glauca × engelmannii) in the Engelmann Spruce-Subalpine Fir and Sub-Boreal Spruce biogeoclimatic zones. Treatments included mounding (with various thicknesses of mineral soil “capping”), patch scarification, blading, disk trenching, and herbiciding. In each trial, five blocks each contained one 48 or 80 tree plot/treatment. Trees were monitored for 10 yr at Mackenzie and 15 yr at Upper Coalmine. Large mounds have had consistent biological success. Tree seedling response to blading was site specific; blading at Mackenzie was not significantly inferior to the best (Ministry mound) treatment, but at Upper Coalmine was no better than the untreated control. West. J. Appl. For. 16(1):9–17.

Establishing white spruce in the Boreal White and Black Spruce Zone Site preparation trials at Wonowon and Iron Creek, British Columbia

Two trials (``Wonowon'' and ``Iron Creek'') in the Prince George Forest Region of interiorBritish Columbia were begun in the mid 1980s toevaluate site preparation treatments for establishingwhite spruce (Picea glauca [Moench] Voss) in theBoreal White and Black Spruce biogeoclimatic zone. The14 treatments (9 or 10 per trial) were: [B.C.]Ministry, Sinkkila, and Bracke mounds; Bracke moundsmanually supplemented with 20-, 14-, or 6-cm cappingsof mineral soil; fertilized Sinkkila mounds; Brackepatches; fertilized Bracke patches; bladed strips;plowed ground; herbicide; and untreated controls,separately with both standard and nominally superior``alternate'' planting stock. With minor aberrations,each trial consists of 5 randomized complete blockseach with one 80-tree plot per treatment; planting wasin spring, 1984 at Wonowon, 1987 at Iron Creek. Alltrees in mounding treatments and the inner 48 trees inother plots were monitored for performance through1998 at Wonowon, 1996 at Iron Creek. The herbicide andplowing treatments, and mounds capped thickly enoughwith mineral soil to inhibit weed regrowth, wereclearly superior to others. In the mounding treatments at Wonowon, survival rateincreased with capping thickness, but, while the 14 and 20 cmcappings were best, significant differences among them were few after 15 growing seasons.In both trials, patchscarification gave poorer results than did plantingwithout site preparation.

Water Uptake by Planted Picea abies in Relation to Competing Field Vegetation and Seedling Rooting Depth on Two Grass-dominated Sites in Southern Sweden

Norway spruce (Picea abies L. Karst.) seedlings were planted on 2-, 3- and 4 - yr - old clear - cuttings. At the time of planting, the ground vegetation on the clear - cuttings was dominated by the grass Deschampsia flexuosa. Effects of various site preparation treatments (mounding and herbicide) were analysed during the first 3 yrs after planting. After the third growing season, seedling dry mass was significantly higher in the herbicide and mound treatments than in the control, but there was no significant difference between the herbicide and mound treatments. During a drought period in August 1995, soil water potentials were lower in untreated plots and in mounds than in the herbicide treatment, but seedling water potentials showed no evidence of water stress. The hypothesis that seedling growth was supported by water taken up from beneath the rooting zone of the ground vegetation during droughts was tested in two ways. By studying the relation between the root morphology of planted seedlings and the rooting density of the ground vegetation, and by comparing the natural abundance of an isotope of oxygen (18

Control of Rough Harvester Ants in Low Water-Use Urban Parks, New Mexico, 1994

Abstract Rough harvester ant control was evaluated in an urban forest park in the city of Albuquerque. Treatments were randomized within blocks and replicated 4 times. Ant mounds were checked for activity, selected and marked, and counts made of active ants on and in the clear area of each mound prior to treatment. Treatments were made on 2 June under sunny weather conditions while ants were active (7:30-11:30 a.m.). Broadcast granular treatments were made by applying measured amounts to a 100 ft2 area around each mound with an Ortho® Whirly-Bird® granular applicator. The broadcast spray treatment was applied with a CO2 pressured back-pack, small-plot sprayer with 6 X-4 tips spaced 20 inches apart. At 60 psi and 4 mph the sprayer delivered 5.63 gal of finished spray per acre. However, the 10 ft by 10 ft (100 ft2) area around each plot was sprayed in each direction to give a spray volume of 11.3 gal per acre. Dry Mound (M) treatments were made by sprinkling measured amounts of each form on the mound area around the entrance hole only. The Orthene 75SP mound drench was applied in 3.78 liters of water sprinkled over a 0.37 m2 area around the center of each mound.

Field performance of outplanted Norway spruce: effects of organic matter amendments and site preparation

Norway spruce (Piceaabies (L.) Karst.) seedling survival and growth response to site preparation methods involving different utilization of humus (forest floor material from the F- and H-layers) and chipped slash were studied on a recently clear-felled spruce site in northern Sweden. Five mounding treatments (pure mineral soil, mineral mound covered by or mixed with either of the two types of organic matter) and two unscarified treatments (with or without a chipped slash mulch) were applied in a randomized block design. Half of the blocks were planted in the year of clear-felling (1990) and the remaining blocks in 1991. Containerized (1/0) seedlings mechanically protected against Hylobiusabietis L. were used. For both planting occasions, seedling survival after 3 years exceeded 90% in most treatments and the occurrence of injuries was significantly (p < 0.05) affected by soil treatments only in the 1990 plantation. In general, the largest seedlings (height, dry weight, needle weight, needle length, leading shoot terminal bud diameter) developed in mounds containing humus, and mounds containing chipped slash produced the smallest seedlings. Mixing chipped slash with mineral soil appeared to suppress seedling growth. The results also indicate that planting delay should be avoided to permit Norway spruce seedlings to benefit fully from the growth-stimulating potential of humus. Successful planting without site preparation might depend on the avoidance of planting delay.