Timber marking as an operational consideration among professional foresters and loggers in Maine.
Professional foresters in Maine were surveyed regarding how and under what circumstances they designated trees for harvest. In addition, Maine's professional loggers were surveyed as to the relative silvicultural outcomes and operational efficiencies of marking/not marking trees prior to harvest. Results indicated that 46 percent of partial harvests administered by forester-respondents were marked prior to cutting, primarily to control the quality of the residual stand. The primary reason for not marking trees prior to partial harvest was that loggers did a good job of selecting trees to cut. In addition, it was apparent that, although some foresters said that they always marked partial harvests, the decision to mark/not mark trees prior to partial harvest was situational for many foresters in the state. Logger-respondents appeared equally divided on whether marking trees before harvest resulted in more or less efficient logging, irrespective of whether trees were felled by chain saw or by feller-buncher or mechanized harvester. However, while over one-third of loggers said that, in their opinion, the quality of silviculture was better when trees were marked, 46 percent said that they did not feel that marking had an effect on the quality of silviculture.
Since 2000, over 95 percent of the acreage subject to timber harvesting in Maine has been partially cut (Maine Forest Service 2004). In addition, as both naturally and artificially regenerated even-aged forest stands mature, commercial thinning has become an important focus for many of Maine's forest managers. Several conferences held in the region in the past decade, in New Brunswick, Canada (in 1998), and Maine (in 1999), have focused on thinning methods and outcomes, illustrating the importance of and interest in this important intermediate silvicultural practice. Among the issues discussed at the conference held in Maine were whether: 1) trees designated for removal in partial harvests should be marked before harvesting; 2) loggers should be charged with choosing trees to be cut as they are logging; and 3) there were perceived silvicultural and/or operational advantages/disadvantages to marking/not marking trees to be harvested or left uncut (Egan 1999). Additional related issues discussed during the meeting included: whether the cutting decisions made by loggers as they are harvesting are equivalent to those that would be made by a forester prior to harvest; whether loggers make consistently appropriate silvicultural decisions from the cab of a harvester or feller-buncher; and whether there is a production loss associated with directing loggers to make cut/leave decisions while they are harvesting.
This paper describes the findings of two recent surveys: one of licensed foresters and another of professional loggers in the state of Maine. The forester survey queried respondents on whether they marked trees for partial harvest, alternative ways used for designating trees for harvest, and their rationales for marking/not marking. The logger survey asked respondents to rate the efficiencies/inefficiencies associated with operating in marked stands, as well as the silvicultural outcomes associated with marking vs. not marking trees prior to harvest. Results of the forester survey were stratified by whether a respondent was a private consulting forester, an industrial forester, or a public sector forester. Logger survey data were partitioned by whether respondents operated conventional or mechanized felling equipment (e.g., feller-bunchers, harvester). For the purposes of this study, harvester refers to machines that fell and perform processing functions, such as delimbing and bucking, at the felling site.
The peer-reviewed literature contains little on the silvicultural outcomes or logging efficiencies associated with marking/not marking forest stands before harvest. Egan (1999, 2001) suggested that the decision to mark/not mark trees prior to harvest is situational, and that tree marking should be considered when one or more of the following conditions exist: logging in complex stands; executing complex silvicultural prescriptions; working with an unfamiliar logger; when a landowner requires it (and is willing to pay for it); logging in restricted areas, particularly when there are minimum stocking and residual tree distribution requirements (e.g., streamside management zones and deer yarding areas); and when logger productivity may be compromised if trees are not marked. Sendak (2002) developed a model for estimating the costs associated with marking in an experimental spruce-fir forest in Maine. He suggested that, although there are direct costs associated with marking, there may be indirect costs associated with not marking, including the time it takes to train equipment operators to make felling decisions, the time it takes for a logger to decide which trees to cut/leave, and the possibility of undesirable silvicultural results if trees are not marked.
However, professional foresters are directly involved in a relatively small percentage of harvests of nonindustrial private forests, which is the dominant forest ownership type in the northeastern United States (Egan and Rowe 1997, Raschka 1998). In Maine in 1998, for example, foresters were involved in approximately 25 percent of timber sales under 1,000 acres, and only 20 percent of timber sales under 100 acres (Egan 200_). In Maine in 2003, licensed foresters supervised 25 percent of harvested acres for woodlots of less than 100 acres (Maine Forest Service 2004). Evidence suggests that forester involvement in the administration of timber sales is less in several states in the region (Raschka 1998, Egan 1993), and even when foresters are involved they don't always mark timber prior to harvest (Egan 1993), sometimes deterred by logger safety liability issues (Egan 1996).
Alternatives to marking trees prior to harvest have also been discussed. According to Smith et al. (1997), "cutting instructions specified in words are normally used when it is either unnecessary or not feasible economically to make sophisticated distinctions between trees ... A much closer degree of control, with less dependence on inspections, can be obtained by marking the trees that are to be removed or those to be left" (p. 443). In addition, the practice of designating trees for harvest by some predetermined diameter limit, rather than marking individual trees, has been criticized (Nyland et al. 1993, Smith et al. 1997, Sokol et al. 2004), and often equated with high grading. Yet despite criticisms, this practice appears to be relatively common in some areas of the northeastern United States (Birch et al. 1992, Egan 1993, Raschka 1998, Egan et al. 2001). For example, a recent study of farm woodlots in northern New England indicated that when farmers engaged in timber harvesting on their forestland, trees were designated by some form of diameter limit in over 25 percent of 470 cases studied. Moreover, while farm woodlots are marked by foresters in approximately 20 percent of cases, the fanner-landowner designated which trees to be harvested in almost half of the cases studied (Egan 200_).
Diameter-limit tree designation appears to be relatively common in other states of the northeast United States. For example, in a case study of Pennsylvania timber harvests, Egan (1993) found that trees were designated for harvest by diameter limit in 24 of 31 (77%) cases studied, while Raschka's (1998) in-depth study of 41 West Virginia timber harvests suggested that diameter limit harvesting was persistent in West Virginia's private forests. However, in a study of harvests conducted by participants in West Virginia's Forest Stewardship Program, Egan et al. (2001) found that approximately 71 percent of harvests were marked for selective cutting, 24 percent were diameter-limit harvests, and 4 percent were clearcuts, suggesting that participants in that program were different in their harvesting behaviors from the state's general forest-owning public.
Results of diameter-limit harvesting have been mixed. In what was characterized as a diameter-limit harvest in West Virginia, sugar maple was found to be regenerating in place of the removed species of yellow-poplar and white ash (Smith and Miller 1987). Many oak species have been found to regenerate poorly after diameter-limit and selection harvesting (Heiligman et al. 1985, Smith and Miller 1987), while on both good and poor quality sites in Ohio, red maple was the most abundant species after heavy diameter-limit harvests (Heiligman and Ward 1993). Sokol et al. (2004) found growth of residual trees in spruce-fir stands after diameter-limit harvesting to be slower than that in similar stands subject to "positive selection harvesting." Although the effects of the practice on non-timber forest values have received little attention, Weakland et al. (2002) found that some populations of migratory songbirds responded favorably to timber harvests in eastern hardwood stands in West Virginia that were cut with a diameter limit of 16 inches. In addition, the authors found that the abundance of the songbird species studied changed little after diameter-limit harvest, and that the abundance of two species, the Canada warbler (Wilsonia canadensis) and dark-eyed junco (Junco hyemalis), was greater in diameter-limit harvested vs. unharvested areas.
Changes in logging technology and work patterns may make the selection of trees for harvest by loggers more challenging. Although equipment manufacturers continue to improve cab visibility, the view from inside a harvester or feller-buncher is not always conducive to making often-difficult silvicultural decisions (Egan 2001). This is particularly true of more complex hardwood and mixed species stands vs. softwood plantations, and when performing complex silvicultural prescriptions in partial harvests that may incorporate improvement, sanitation, and regeneration cutting in the same operation. Logging at night may add another level of complexity to making the best silvicultural decisions, despite the use of workplace illumination on mechanized felling equipment. Moreover, feller-bunchers and harvesters approach trees from only one direction, and the operator rarely has an opportunity to evaluate the entire tree before making felling decisions (Egan 2001).
Licensed foresters and professional loggers in Maine were mailed separate surveys that posed questions related to marking trees prior to harvest. Multiple mailings--a cover letter and survey, followed by a reminder postcard, and, finally, a second cover letter and survey--were used in both surveys to increase the response rate and mitigate bias due to nonresponse (Dillman 1978). A comprehensive mailing list of 670 licensed foresters in Maine was provided to the investigators. Since licensing is mandatory for foresters in the state, virtually all professional foresters who practiced in Maine received the survey. Foresters responded to the following questions related to pre-harvest timber marking:
* Approximately what percent of thinnings and other partial harvests do you mark?
* If (when) you do mark trees, why?
* If (when) you do not mark trees, why not?
* When you don't mark, how do you designate trees to be harvested?
Mailing lists of loggers in Maine were obtained from two sources: lists of loggers who had been trained by the Certified Logging Professional (CLP) Program and a list of all loggers who had filed a mandatory harvest notification with the State of Maine in 2000. A French version of the survey was mailed to French-speaking loggers from eastern Quebec who worked in Maine. We anticipated that the information from the harvest notifications would include loggers not on the CLP mailing lists. Overall, 2,870 surveys were mailed to Maine resident loggers and 609 surveys (in French) were mailed to Quebecois loggers who worked in Maine. In addition, phone interviews of a random sample of 100 survey non-respondents after the third mailing were conducted for Maine resident loggers.
Loggers responded to the following questions related to pre-harvest timber marking:
* On what percentage of your jobs during the last year was the wood marked/painted by a forester?
* Do you generally find it more/less efficient to log if the trees are marked beforehand?
* For respondents who operate a feller-buncher or harvester, is it more/less efficient to log if the trees are marked beforehand?
* For respondents using a feller-buncher or harvester, does marking trees beforehand result in better/worse/about the same quality of silviculture?
Categorical data analysis methods were used to describe the association between timber marking behaviors and whether forester-respondents' worked as consulting or private industry or public sector foresters. The association between loggers' responses related to their perceptions that marking made logging more/less efficient and whether they used chain saws or mechanized equipment to fell was also explored. In addition, comments from survey respondents were content analyzed and included to add depth to some survey responses.
Results and discussion
The forester survey
Of the 670 forester surveys, 433 were completed and returned (response rate = 65%). Using methods tested by Armstrong and Overton (1977), nonresponse bias was estimated using chi-square analysis to determine whether survey responses to a battery of questions related to why respondents did/did not mark trees before harvest were dependent on whether a survey participant was an early or late respondent. Respondents to the first survey mailing were compared with those who responded to the third mailing. None of the responses were dependent upon when a respondent returned the survey (alpha = 0.05).
Of those responding to the survey, approximately 39 percent described themselves as industry or procurement foresters, 36 percent were consulting foresters, 9 percent were public lands foresters, and 17 percent were placed in an "other" category that contained relatively small numbers of licensed foresters who described their profession as private landowner, retired, academic forester, surveyor, land management, sales person, utility forester, engineer, and silviculturist (Table 1).
Forester survey participants were asked to respond to the question, "Approximately what percent of thinnings and other partial harvests that you administer do you mark?" Overall, respondents indicated that they marked approximately 46 percent of thinnings and partial harvests that they administered. Approximately 73 percent of partial harvests administered by public lands foresters were marked, compared with 54 percent for private consulting foresters, and 31 percent for private industry foresters.
When asked why they marked trees prior to harvest, approximately 80 percent of respondents cited better control over the quality of the residual stand. This result included 94 percent of public lands foresters, 90 percent of consulting foresters, and 70 percent of foresters employed directly by forest industry. Analysis indicated that this reason given for marking trees was dependent (alpha = 0.05) on whether the respondent was a public sector forester, private consultant, or industry forester (chi-square = 25.99; p < 0.001) (Table 2). Although fewer (25%) survey participants responded that the loggers they worked with preferred trees to be marked, chi-square analysis suggested that this response was again dependent on whether the respondent was a public sector forester, consulting forester, or industry forester (chi-square = 8.91; p = 0.012) (Table 2).
When asked why they did not mark trees prior to harvest, the most common response (60% of all respondents) was that loggers did a good job without marking, with industry foresters (68%) offering this response more often than consulting (58%) or public sector (37%) foresters (Table 2). Tests again indicated dependence between foresters' employment subgroups and responses to this question (chi-square = 12.61; p = 0.002). Although tests indicated a lack of dependence between employment subgroups and a response indicating that it was too expensive to mark trees (chi-square = 1.60; p = 0.450), there was an association between employment subgroup and a response indicating that there was not enough time to mark trees prior to harvest (chi-square = 36.11; p < 0.001), with this reason most often cited by industry foresters.
Moreover, survey responses indicated that the most common way of designating trees for harvest when trees were not marked was through instructions to loggers (78% of all respondents) (Table 3). This response was dependent on forestry employment subgroup (chi-square = 15.35;p < 0.001), with industry foresters most often citing this reason for not marking. Cited by only 26 percent of all respondents, specifying trees to be cut by diameter limit harvesting was not found to be dependent on forester subgroup (chi-square = 3.83; p = 0.147). Other ways of designating trees to be harvested that were cited by respondents included designating the boundary of a clearcut (17% of respondents), and focusing on the removal or maintenance of a species or species group, especially aspen and balsam fir (10%).
Written comments from foresters helped add some depth to their survey responses. Some foresters indicated that it was their professional duty to mark partial harvests. For example, a forester who marks all partial harvests that he administers wrote, "I am the forester. How else can I practice silviculture. Loggers, although knowledgeable, are not foresters." Another said that "I always mark--it is a sad mark on the (forestry) profession to respond (that they do not mark timber)." An industry forester who marked only 10 percent of partial harvests he administered wrote, "My employer does not recognize the benefits to marking wood, and will not listen. In their mind, production is all that's important. In my opinion, this is wrong." Other foresters addressed their perception of operational efficiency when trees are marked before harvest. For example, one stated that, "Logging is faster (because) decisions (on which trees to harvest) are made beforehand."
Other respondents supported the notion that the decision to mark is situational, depending on either the silviculture prescribed or the needs and demands of the landowner. For example, one forester stated, "I mark when the instructions are too complicated to explain (to the logger). I do not mark when instructions are not too complicated." Another stated that he marks "when the landowner requests it and is willing to pay for it." Foresters who said that they rarely, if ever, marked partial harvests indicated that the loggers with whom they worked were capable of making cut/leave decisions. According to one respondent who marked 5 percent of partial harvests, "with proper training, logging contractors will harvest the prescription that is given them," while another who did not mark any partial harvests appeared to agree: "I work with the same operators over and over; they do the best work on tree selection and residual stand, with training."
The logger survey
Completed surveys were received from 692 Maine loggers (response rate = 24%), and 191 from loggers who live in eastern Quebec and work in Maine (31%). Because 100 logger nonrespondents from Maine were surveyed by phone, nonresponse bias for that state's logger survey was tested directly by comparing responses from those who had responded to the mail survey to those who did not respond to the mail survey but later responded to the phone survey. Results suggested that survey respondents and nonrespondents were from the same population.
Loggers reported that 27.6 percent (range = 0% to 100%) of the jobs that they harvested were marked by a forester in the previous year. The average number of jobs marked per year for logger-respondents was 1.6 (median = 1 job per year; mode = 0 jobs per year). Overall, slightly more than half of the logger respondents who used manual felling said that it was more efficient to log when trees were marked before harvest. Response percents were similar for those who operated a feller-buncher or harvester (Table 4). Chi-square analysis indicated that responses related to the relationship between timber marking and logging efficiency were not dependent on whether respondents used chain saws or mechanical felling equipment.
In addition, over a third of loggers who use feller-bunchers or harvesters to fell trees said that, in their opinion, marking before harvesting resulted in better silviculture than if trees were not marked, while less than 20 percent said that it resulted in worse silviculture. The remainder, a plurality, indicated that they felt that there was no difference in the quality of silviculture between marked and unmarked stands that they harvested.
Several written comments from logger-respondents suggested that their preferences for operating in marked vs. unmarked stands was dependent upon the ability of the forester to designate trees for harvest in a manner conducive to efficient logging operations. For example, one logger wrote that it is "totally dependent on the person marking the timber; some have good knowledge of timber removal, some very poor." Another stated that "most foresters have never harvested wood and don't understand how it is done. Most will not listen to suggestions or information the logger has."
Other loggers indicated that the operational efficiency associated with marking/not marking timber was dependent on the equipment operator. One stated "a good feller-buncher operator should not need marked trees." An operator of a mechanized felling machine suggested that it was dependent on other circumstances, such as available light and visibility: "(Operating in marked timber) could be efficient--(but) sometimes looking for paint slows you down, especially at night." Another logger cited the nature of the logging chance, stating that "it depends on the stand of wood and the situation of the woodlot."
As the forests of Maine, as well as those of much of the rest of New England, are increasingly harvested using partial harvest methods, the question of how to best designate trees for harvest persists. Survey responses from foresters suggested that the decision to mark or not mark trees prior to harvest was situational for most foresters; 70 percent of respondents indicated that they marked some harvests and not others. In addition, results of this study revealed that the most often cited reason for marking trees prior to harvest was to control the quality of the residual stand; when foresters did not mark trees, it was most often because the respondent felt that the logger did a good job of selecting trees to harvest. Consistent with the latter result, when trees were not marked, trees were most often designated for harvest through instructions given to the logger. These results suggest that several factors are considered when deciding whether trees should be marked before harvest, including the silvicultural system being applied, the experience of the logger, and the complexity of the stand to be harvested, especially in terms of its species composition, age, and structure. Foresters identifying themselves as working for forest industry more often cited time constraints when explaining why they did not mark trees prior to harvest, and were less likely than consulting or public sector foresters to say that they marked trees because loggers preferred it.
Loggers in Maine appear evenly divided on the operational benefits of marking trees before harvest, and a plurality believe that the quality of silviculture is about the same regardless of whether trees are marked or not. However, the experience of the person doing the marking and her/his appreciation for logging efficiency appear to be keys to efficient harvesting when timber is marked. This suggests that 1) marking timber should not be considered an entry-level forest management task; and 2) new timber markers should receive significant guidance in both silviculture and forest operations before making cut/leave decisions independently. In addition, as indicated by one logger, following paint at night for mechanized crews can be a problem. However, the ability of mechanized crews to make good silvicultural decisions at night in unmarked wood was not addressed in this study.
As foresters, landowners, and loggers continue to balance timber operation costs and efficiencies with forest sustainability and timber harvest revenue, how to best designate trees for harvest in partial cuts will continue to be a silvicultural as well as an operational consideration. For many, this will most likely be done on a harvest-by-harvest and operator-by-operator basis. However, despite differing opinions on the necessity of timber marking, little is known of the short- and long-term costs and benefits of marking/not marking and key questions remain. Are the cutting decisions made by loggers as they are harvesting equivalent to those that would be made by a forester prior to harvest? Can loggers make consistently appropriate silvicultural decisions from the cab of a harvester or feller-buncher? Is there a production loss/gain associated with directing loggers to make their own cut/leave decisions while they are harvesting? What are the short-term costs--as they accrue to the forest management firm/landowner and logger--associated with marking timber prior to harvest and allowing loggers to make cutting decisions? In addition, what are the long-term silvicultural costs, if any, associated with carrying undesirable trees to the next thinning or to the end of the rotation if poor cut/leave decisions are made? While there may be situations in which pre-harvest timber marking of individual cut or leave trees may be unnecessary (e.g., clearcuts, removal of a particular species), with increasing concerns over the sustainability of timber resources and the efficacy of conducting thinning and other partial harvest operations, the costs and benefits of timber marking vs. other tree designation methods deserve further clarification.
Armstrong, J.S. and T.S. Overton. 1977. Estimating nonresponse bias in mail surveys. J. of Marketing Res. 14(8):396-402.
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Andrew F. Egan*
The authors are, respectively, Professor, Dept. of Wood and Forest Sciences, Laval Univ., QC, Canada (Andrew.firstname.lastname@example.org); and Research Assistant, Dept. of Forest Management, Univ. of Maine, Orono, Maine (Stephanie_Phillips@umit.maine.edu). This paper was received for publication in July 2005. Article No. 10086.
* Forest Products Society Member.
Table 1. -- Licensed foresters in Maine who responded to the survey, by category of forester. Category Industry/procurement (n = 166) 39% Consulting (n = 155) 36% Public lands (n = 37) 9% Other (includes private landowner, retired, academic, surveyor, 17% land management, sales, utility forester, engineer, and silviculturist) (n = 75) Table 2. -- Summary and chi-square analysis of forester responses to questions related to 1) why respondents mark trees prior to harvest; and 2) why respondents do not mark trees prior to harvest. Forestry employment subgroup Consulting Industry Public foresters foresters foresters Chisquare p-value % 1) Why do you mark trees prior to harvest? (n = 408) Quality of 90.1 69.5 94.3 25.99 <0.001 (a) the residual stand Logger 32.4 18.3 31.4 8.91 0.012 prefers it 2) Why do you NOT mark trees prior to harvest? (n = 409) Loggers do a 57.9 68.3 37.1 12.61 0.0002 good job without marking Too 22.7 23.8 14.3 1.60 0.450 expensive Not enough 10.5 39.6 20.0 36.11 <0.001 time (a) Underlined p-values indicate the response is dependent on a respondent's forestry employment subgroup at alpha = 0.05. Table 3. -- Summary and chi-square analysis of forester survey participant responses to the question: "When you do not mark trees prior to harvest how do you designate trees to be cut?" Forestry employment subgroup Consulting Industry Public foresters foresters foresters Chi-square p-value (%) Instructions 78.1 87.1 57.6 15.35 <0.001 (a) to the logger (n = 371) Diameter limit 25.6 28.6 12.1 3.83 0.147 (n = 371) (a) Underlined p-values indicate the response is dependent on a respondent's forestry employment subgroup at alpha = 0.05. Table 4. -- Loggers' responses to questions about operational efficiency and quality of silviculture between marked and unmarked stands that they have operated in the past year. When trees are marked More Less (%) Manual felling efficiency 50.4 49.6 (n = 671) Mechanical felling efficiency 50.2 49.8 (n = 287) Better Worse About the same Mechanical felling quality of 35.3 18.7 45.9 silviculture (n = 287)
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|Author:||Egan, Andrew F.; Phillips, Stephanie|
|Publication:||Forest Products Journal|
|Date:||Sep 1, 2006|
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