Sugar Bush Management – Planning and Management Options

operations where the number of taps is often limitedeither by property boundaries or stand area, promotingnew sugar maple crop trees through thinning issometimes difficult to justify because traditionalmanagement methods could mean the loss of tapsand a decrease in syrup production. As a result, manysmaller woodlots have not received the managementneeded to help them grow to their maximum potential.Management ObjectivesThere is no forest product that is more sustainable thenmaple syrup, and proper management should help keepa woodlot producing sap for many generations. Somemaple operations in Ontario for instance, have beenin continuous production since the 1800s. For smallscaleoperations, difficulties in promoting growth ofyounger maples, while at the same time maintaining ahigh number of taps, offer challenges to the long-termviability of individual sugar bushes. There is simply notenough space to plan for the replacement of overmaturetrees if the landowner wants to maintain the optimumnumber of taps. As a result, the management objectivesfor the small-scale maple operation should differ (if onlyslightly) from larger ones by focusing on promoting thegrowth of healthy trees. Manipulation of the forest usingtraditional methods may be inappropriate.Managing for improved tree health and vigour has itsbenefits and is one of the primary objectives for thesmall-scale operator. Figure 1 shows two tree sections;Tree A comes from a well-managed woodlot whileTree B comes from an unmanaged woodlot. The bigdifference in these two maples is their age – Tree A is50 years old which is large enough to tap; Tree B is 75years old and is still too small to tap. It stands to reasonthat Tree A was a healthier, more productive tree.growing in a well-managedsugar bush, the other isgrowing in a woodlot thatis not managed but stillin production. If thereis only a 1 mm averageannual growth differencebetween the two trees, themanaged tree could growto be tapped as much as10 years sooner then theunmanaged tree. Over 100 years this could add up toas much as $600 difference in syrup production. Thatis $600 dollars per tree – multiply this by the number ofcrop trees in your sugar bush and the number becomesquite large. Of course this is just an example based on anumber of assumptions but it comes from growth datafrom an actual maple management study.The Management CycleFigure 1: Tree sections from a managed(Tree A) and unmanaged (Tree B) sugarbush.Think of your approach to management as a series ofsteps (Figure 2) that are repeated about every 20 years.In the early years, activities are focused around planningand inventory. Later on, depending on your objectivesand the inventory, you may decide to thin your woodlot.After this period of activity you will probably need todo nothing more then monitor your sugar bush for anumber of years to see how well it is doing. Theseplanning steps are common to most forest operationsregardless of scale.Improved growth is one of the primary benefits frommanagement – if a tree grows faster (Tree A, Figure 1),it will produce syrup sooner. The results of improvedgrowth can be dramatic. Consider two maples bothof which are 12.5 cm (5 in.) in diameter; one maple isFigure 2: The Management Cyclecontinued next page...OWA - Dedicated to the Wise and Profitable Use of Ontario’s Private Woodland Resources 9

An Introduction to Sugar Bush Management 101The following sections briefly describe one approachto managing the small-scale sugar bush. As an owner,it is important that you seek out the best possibleinformation and advice. Mistakes are hard to correct sotake the time to research all aspects of management.If you aren’t comfortable with doing it yourself, hiresomebody with experience in managing a sugar bush.The money you spend now to get an expert opinion maywell save you thousands of dollars later. Don’t be afraidto ask for help.Does Your Sugar Bush Need Thinning?The inventory tells you what you have. This is criticalwhether you own one acre or 100 acres because youcannot make informed decisions without first knowingwhat you have and what kind of condition it is in. For thepurposes of small-scale sugar bush management, youonly really need to know three pieces of information: thenumber, size and species present in your sugar bush.Information on the general condition of the trees is alsocollected and provides an indication of what there is towork with. Good or bad, you are stuck with what youhave, but keep in mind, improved health is one of themain reasons you manage your sugar bush in the firstplace. The better quality trees will be left to grow whileTable 1: Sugar Bush Stocking Recommendations (metric)AverageDiameter (cm)Numberof TapsRecommendedTrees per HaNumber ofTapsper Ha< 10 0 > 680 010 to 25 0 210 to 680 025 to 37 1 150 to 209 150 to 20937 to 50 2 100 to 149 200 to 29850 to 63 3 66 to 99 198 to 297> 63 4 < 66 < 264the poorer quality ones will be identified and markedfor removal.Management decisions are made by comparing whatyou have to what is recommended. Table 1 shows astocking chart for maple syrup bushes. It is a guidelinefor determining the recommended number of croptrees per unit area. In this case, numbers are shownin has and centimetres; an imperial stocking guidein inches and acres is available from the author (seecontact information at the end of this article). Crop treeselection is discussed later in this article.For example, if you are tapping two ha (about 5 acres)of land and your inventory shows an average treediameter of 26 cm, the stocking guide indicates thatthe recommended number of crop trees is between150 and 209 per ha. However, because the diameteris closer to the smaller diameter (25 cm) in the range,the number of trees should be closer to the upper limitrecommended (about 200). Therefore, for this twoha sugar bush, the stocking chart would recommendapproximately 400 trees.If your inventory indicates that you have more then 200trees/ha, your sugar bush is overstocked and thinningis recommended. If your sugar bush has less then 200trees/ha it is understocked and thinning is not advised.An inventory of 250 trees per ha would indicate thatabout 100 trees (250 - 200 x 2) should be removedfrom the sugar bush.From the table it is also possible to determine therecommended number of taps per ha. A pure standof maple two ha in size, with an average diameter of26 cm, should have about 400 taps (26 cm is in the 1tap single tap 25-37 cm diameter class). However, thisvalue may be high because other species in the sugarbush (e.g., beech, ash and hemlock) are counted in theinventory. In other words, the recommended 200 treesper ha could be a mixture of species, the bulk of whichwould be maple. It is seldom possible to achieve the10 OWA - Dedicated to the Wise and Profitable Use of Ontario’s Private Woodland Resources

ecommended number of taps per ha when dealing withsmall-scale sugar bushes.This may seem complicated, but it really isn’t. Simplydetermine the average diameter of your forest and theaverage number of trees per ha. Assume that all thetrees are maple and use the stocking chart to determineif you are overstocked or understocked.If your sugar bush is overstocked thinning isrecommended. Walk through the forest, first markingthe crop trees that will not be harvested (see nextsection). In this example, about 400 trees should bemarked. Next, mark the trees (about 100) that will beharvested (using a different colour of paint). Onceboth the crop and removal trees are marked, cuttingoperations can be conducted.Harvesting cautions:• Never harvest more then 1/3 of the stand at anyone time – that is leave 2 trees and take 1. In theexample given, about 1/4 of the trees are going tobe removed.• Poor harvesting operations can ruin a woodlot – getadvice on when and how to harvest properly. Beespecially careful of the identified crop trees andwork safely.• Not every tree will be marked as either a crop treeor a removal tree – many trees often smaller indiameter will be left to grow. Generally, ignore treesthat are growing in the understory – if the tree isn’tinterfering with a crop tree then it can be left alone.How Do You Choose a Crop Tree?Crop trees are those that will be favoured throughmanagement over the next few decades and eventhough they may not be tapable when the woodlotis thinned, they represent an investment in the futureof the sugar bush. If crop trees are a reflection of thefuture, it is important to choose the better quality treesin the woodlot because they will probably be a longtermsource of sap. The following list of characteristicscan be used to identify crop trees in the sugar bush.• Crop trees tend to be maple although otherspecies may be identified as well – pure stands ofmaple are not generally recommended. Non-maplecrop trees will probably reduce the overall numberof taps, but keep in mind your primary objectiveis to grow a healthy forest (think forest health firstand sap production second). Foresters alwaysrecommend a diversity of species, even in a sugarbush.• Crop trees have larger crowns. Crown size isimportant for maple sap production – largercrowned trees tend to produce more sap.• Crop trees tend to have good form with no obvioussigns of decay or damage. Favour straight treeswith no major forks, which may break under heavysnow or wind. Remove trees with obvious cankersor decay.• Crop trees should have well-rounded crowns.Crowns that are on one side of the tree only willnever grow to their potential.continued next page...W &CWEAVER& CURTISBARRISTERS and SOLICITORS25 Main StreetP.O. Box 1660Brighton, OntarioKOK 1HODavid S. Curtis, R.P.F.Lawyer and Mediatordirect: 613-475-4755fax: 613-475-4646dcurtis@magma.caBOOKSWoodlot, Forestry& Nature titles2003-2004 Book Listis now available!Contact us for your FREE copyphone 613-233-4283, fax 613-233-0877email = mail@forestshop.comwww.forestshop.comOWA - Dedicated to the Wise and Profitable Use of Ontario’s Private Woodland Resources 11

• Crop trees are dominant or codominant in thecanopy – a crop tree should not be suppressed byits neighbour. Smaller then average trees may bechosen as crop trees as long as you recognize thattapping may not occur for a number of years.How Do You Choose a Removal Tree?After the crop trees have been identified, it isnecessary to mark the trees that will be removedduring a harvesting operation. This is usually donewith two paint marks, one on the main stem andanother down near the base of the tree. In the exampleprovided, about 100 trees need to be removed from thetwo ha sugar bush. Keep in mind the number of treessuggested is determined using the inventory and thestocking guidelines. Do not be alarmed if less then therecommended number of trees are actually markedfor removal – this is just a recommendation that maybe impractical for the sugar bush in question. Treesare never evenly spaced nor are they uniform in size,and as a result some interpretation of the guidelinesis necessary. Harvested trees should be those thatinterfere (or will interfere in a few years) with crop trees.There are a number of methods of determining whichtrees need to be removed. The first called the TreeSpacing Method uses a table to determine how muchspace a crop tree needs around it.Table 2: Tree Spacing Method for DeterminingCrop Tree Distances (m)Diameter (cm)15 20 25 30 35 4015 5.820 6.1 6.425 6.4 6.7 7.030 6.7 7.0 7.3 7.935 7.0 7.3 7.6 8.2 8.540 7.3 7.9 8.2 8.5 8.8 9.4Table 2 lists the recommended distances in metresbetween trees of varying diameters and their nearestcompeting neighbour. For example, if a 20-cm noncroptree were 5 m away from a 30-cm crop tree,it would be a good idea to mark it for removal. Therecommended distance between a 20-and 30-cm treeis 7 m. If that tree were greater than 7 m away fromthe crop tree, it would not be necessary to remove itbecause of spacing considerations.Another method of determining what trees need to beremoved is called the Crown Release Method. Usingthis method, a tree is removed if its crown comeswithin a specified distance from the crown of a croptree. Freeing space around the crop tree allows forfuture crown growth between thinnings. Generally,a distance of between 2 and 3 m is recommendedbetween crowns for trees greater then 8 cm indiameter. For many producers the crown releasemethod is easiest to apply in the sugar bush.Regardless of the method by which removal trees areidentified in the sugar bush, it is important to keeptrack of the trees that have been marked. Using aclipboard and a tape measure, the diameters of allthe marked trees can be recorded. This informationvalidates the work done to date – were too many ortoo few trees marked? The marking tally allows you tocheck and adjust your marking before the trees are cutin the woodlot.Planning For the Next Generation of Maple TreesAs mentioned it is more difficult to manage forregeneration in the small-scale sugar bush. If you arefortunate enough to own a woodlot with a range ofdiameters and ages, then the next generation of treesmay well be taken care of already. If however, yoursugar bush is roughly all the same age, and most ofthe trees are around the same diameter, then growingnew trees can be a problem. Harvesting will open thecrown up enough to promote the growth of youngmaple saplings but it will be almost impossible to get12 OWA - Dedicated to the Wise and Profitable Use of Ontario’s Private Woodland Resources

a range of diameters and ages. If this is the case – donot worry.It is important to look at the bigger landscape – isyour sugar bush part of a much larger forest? If so,is the larger forest more representative of the ideal?Foresters promote diversity and as a result tend tofrown on stands consisting of one single species.Diversity is a good thing but less diversity in the smallscalesugar bush is not necessarily a bad thing. Thinkback to the beginning of this article – your objective isto grow the healthiest trees possible.Future articles in this series will cover other aspects ofgrowing and operating a healthy sugar bush.Mark Richardson is a forester working for the EasternOntario Model Forest. He invites comments andquestions on sugar bush management and can bereached in Kemptville at (613) 258-8416 or by e-mail at.Play a Bigger Role in the OWA!Help us meet the challenges of a growingorganization and consider adding yourvoice to the OWA’s board of directors. Electionswill be held for seven positions on the provincialboard at our February AGM in Belleville. Theseseven positions are in addition to the chapterrepresentatives who are appointed to theprovincial board by local OWA chapters.Roles and Responsibilities of an OWA Director:• Available to attend four or five eveningmeetings a year (a conference call ispossible);• The positions of president and vice-presidentare elected by the provincial board ofdirectors (from the seven board memberselected at the AGM);• Review of information provided by theexecutive director between meetings; and• Provide input into the general supervision ofOWA’s affairs and make recommendations tothe general membership.If you or someone you know is interested, pleasecall Wade Knight at the OWA office, or a memberof the nomination committee. Nominations will beaccepted up until the election.Your OWA Nomination CommitteeVictor Roland (519) 335-3944or fax (519) 335-3914Art Shannon (705) 892-2566or e-mail OWA - Dedicated to the Wise and Profitable Use of Ontario’s Private Woodland Resources 13