Landcare Community Leadership Regional Landcare Facilitator presentation
STATE OF THE ENVIRONMENT LAND AND SOIL...Comparisons between Landcare Research’s 1996 and 2012...
Transcript of STATE OF THE ENVIRONMENT LAND AND SOIL...Comparisons between Landcare Research’s 1996 and 2012...
About 15,000 hectares of our flat to gently rolling land is on the Poverty Bay Flats, with much of the remainder being flats around Uawa, Waiapu and Tikitiki. The region is located on an actively rising fold of the earth’s crust, the crest of which is the bush-covered Raukumara Range. Geologically young sedimentary rocks extend eastwards along the coast, dominated by soft mudstones containing shrinking and swelling clay minerals such as bentonite and montmorillonite. Because of a high rate of uplift (4mm per year), tectonic crushing, soft rocks, mild climate and the removal of much of the original forest cover, Gisborne experiences some serious erosion problems. This presents a big challenge for sustainable land use.The Poverty Bay Flats have fertile and versatile soils able to be worked by
LAND AND SOILPRINCIPAL FINDINGS y Cropping trends in the district
show that maize, sweetcorn, grapes, citrus, squash and kiwifruit are the most significant summer crops. The area planted in grapes is still declining slightly, and squash production is increasing on land outside of the Poverty Bay Flats.
y 60% of Overlay 3A, the most severely eroding land, is now covered by a completed workplan.
y From 2013 to 2015, 1625 hectares in new Erosion Control Funding Project (ECFP) grant approvals have been applied. Indigenous reversion and Manuka planting are becoming more favoured treatment methods.
y Forestry harvest in the district is continuing to increase with the 2013-2015 area more than triple of that harvested in 2002-2005.
y Severe weather events in areas of recent forestry harvest continue to have major environmental impacts. Work is underway with the sector to try and find better ways to mitigate or prevent these.
y Large areas of the Poverty Bay Flats and parts of Gisborne City are vulnerable to liquefaction in a large earthquake. More detailed mapping has been completed which will enable better planning and development processes.
STATE OF THE ENVIRONMENT
THE GISBORNE DISTRICT COVERS APPROXIMATELY
839,000 HECTARES
596,000HECTARES
IS STEEP HILL COUNTRY
71,000HECTARES
IS FLAT/GENTLY ROLLING LAND
42%OF GISBORNE’S LAND IS
PASTORAL FARMING
ONLY 5DAIRY FARMS OPERATE
IN THE DISTRICT
THE MOST SEVERELY EROSION PRONE LAND IN THE NORTH ISLAND IS FOUND IN THE GISBORNE DISTRICT
machinery. River stopbanks afford a good level of protection from flooding, the climate is favourable and infrastructure is well developed. As a result these flats are the most productive and intensively farmed areas in Gisborne, where a wide variety of enterprises are established including orchards, vegetable cropping and vineyards. The combination of soils and climate means that horticulture is a more economic landuse than dairy farming. They are a major contributor to employment and local GDP.Land used for pastoral farming is mainly mixed sheep and beef farms, although this has been dropping in recent years as eroding land has been planted in exotic forest or willows and poplars. Manuka regrowth is now being valued as an important nectar source for bees and honey production.
GISBORNE 2013-2015
EXOTIC FOREST NOW COVERS
20% OF THE DISTRICT
THE LAND RESOURCE
Comparisons between Landcare Research’s 1996 and 2012 Land Cover Database show the increase in forestry within the district – increasing from 16% of the district to the current 20% with 172,310 hectares now in pines. Overall native forest cover across the district also increased by 3,630 hectares as a result of Kanuka and Manuka regeneration. Reflecting this change in landuse the area under pasture dropped from 47% of the district to 42% - a reduction in 29,410 hectares. There was a slight increase in land used for cropping of 930 hectares over the time period and the urban landuse expanded by 110 hectares.
Sheep and beef numbers in the district have increased after a dip in 2013 to numbers similar to 2011. Deer numbers are still below peak levels reached in 2004 and declining. The number of dairy grazing cattle spiked in 2013 but have had a sharp decline. There are five dairy farms in the Gisborne District. Combined they milk 3,600 cows. In 2013 there were 9,000 dairy cows and heifers in milk or calf in the region, mainly winter grazers and in 2014 there were 8,000. The trend for a high percentage of Gisborne’s dairy cattle being grazed not milked, continues as cattle from Bay of Plenty and Hawkes Bay are wintered in Gisborne.
Source of data: Statistics New Zealand Agricultural Tables 2002-2013, NZ Statistics Infoshare Agriculture Tables 2013, 2014, 2012 Agricultural Census Livestock Tables (published 2013). Agricultural production Statistics June 2014 (final). 2015 results for Gisborne available 11 May 2016. Note: The total dairy numbers includes dairy cows and heifers in milk or calf, and other types of dairy cattle, such as rising one-year old cattle and bulls for breeding.
2010 2011 2012 2013 2014
Total sheep 1,589,785 1,517,015 1,547,294 1,503,378 1,602,270
Total beef cattle 262,073 272,017 267,599 260,456 277,484
Total deer 15,093 17,196 17,323 18,883 17,871
Total dairy cattle(primarily grazers)
10,535 17,806 17,095 19,332 15,153
Total horses 1,644 1,168 1,193 1,424 1,033
Land cover type1996
Area (ha)1996
% of District2012
Area (ha)2012
% of District
Plantation Forest 137,750 16% 172,310 20%
Indigenous Forest 185,960 22% 185,140 22%
Manuka/Kanuka 72,490 8.6% 76,940 9.2%
Willows and Poplars 5,140 0.6% 6,150 0.7%
Scrub 3,650 0.4% 3,600 0.4%
Pasture 394,040 47% 354,970 42%
Cropping 15,750 1.9% 16,680 2%
Urban 2,790 0.3% 2,900 0.3%
AREA UNDER PASTURE DROPPED
5%4%
INCREASE IN FORESTRY
LAND COVER CHANGES Scale 1:650,000
Short-rotation cropland
Orchard vineyard and other perennial crops
High producing exotic grassland
Low producing grassland
Broadleaved indigenous hardwoos
Willow and poplar
Indigenous forest
Manuka and/or kanuka
Exotic frest
Forest - harvested
N
Rangatira Stud bull that sold for $100,000 at a NZ farm sale in Muriwai, Gisborne
LIVESTOCK
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WINTER STATE AND TRENDSIN WINTER 2015
2212.20HECTARES
WERE PLANTED IN FODDER CROPS
THE MOST COMMON CROP TYPES FOR WINTER WERE
PLANTAIN LUCERNE
Although pasture is the most common summer crop there is a slight decrease from previous years. Maize and sweetcorn were the most common followed by grapes, citrus, squash, and kiwifruit. Crop rotation explains fluctuations of areas occupied by crops such as maize/sweetcorn, squash, tomatoes, and lucerne. Squash production declined in the Poverty Bay Flats, but a significant proportion of squash is grown outside the Flats, raising the total of squash production for the region.Tomatoes decreased significantly in 2012/13 and have remained steady since then. Citrus and kiwifruit have been stable for the last three years. Grapes have been declining since 2008 although the drop has slowed. There is a declining trend for tamarillos, stonefruit, and avocadoes and processing vegetables, whereas persimmons have experienced significant growth.
SUMMER STATE AND TRENDS
IN SUMMER 2014/2015
36%OF SUITABLE LAND WAS OCCUPIED BY PASTURE
THE NEXT MOST COMMON CROP TYPES FOR SUMMER WERE
MAIZESWEETCORN
The largest area of fodder crops was grown on the East Coast, including Tikitiki, Ruatoria, and Tolaga Bay. Plantain was grown in every location surveyed. Plantain is a high protein perennial herb that adapts well to drier regions, less fertile soils, and heavy clay soils. Lucerne is a legume that is also very tolerant of dry conditions and fixes nitrogen in to the soil. In Te Karaka and Whatatutu, lucerne and oats were prevalent. Chicory was found in large numbers on the Poverty Bay Flats.
TOTAL HECTARES OF WINTER FODDER CROPS PER LOCATION
GRAPES
PIP AND STONE FRUIT
CROPPING
0
100
200
300
400
500
600
East Cape/ Ruatoria
Tolaga/ Tokomaru
Motu/ Matawai
Poverty Bay Flats
Te Karaka/ Whatatutu
Tiniroto
480.56 482.12
345.15
466.77
296.93
49.69HE
CTAR
ES
LOCATION
0
100
200
300
400
500
600
HECT
ARES
YEAR
2007/08 2008/09 2009/10 2010/11 2011/12 2012/13 2014/15
Pip and stone fruit totalApples/pearsPersimmonAvocadoStone fruit
1500
1750
2000
2250
2500
2750
YEAR2007/08 2008/09 2009/10 2010/11 2011/12 2012/13 2014/15
HECT
ARES
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The Gisborne District is well known for its soft rock soil erosion – on a scale and severity greater than any other part of New Zealand. Our natural erosion susceptibility has been aggravated by deforestation as indigenous forests were progressively cleared for pastoral farming over the late 19th and early 20th century. Efforts to re-establish vulnerable hill country areas in trees began in the 1950’s and came together as the East Coast Project in 1970 that set about planting exotic forests in the back country, and small woodlots and strategically placed trees in the pastoral forelands. Later this was changed to better match land use to land use capability. These schemes have seen erosion protection plantings such as poplars and willows, the planting of forestry, native reversion and most recently Manuka plantations for honey production established to help combat the worst of the region’s erosion.
THE SUSTAINABLE HILL COUNTRY PROJECT (SHCP)Works plans were required to have been submitted by 2011 and treatment works are to be completed by 2021. While the deadline for the completion of works plans has now passed with a number of properties still yet to complete their plans, progress continues to be made. In 2013, 2014 and 2015, land and soil resources staff continued to liaise with affected landowners and visit properties to develop individual plans in collaboration with property owners and managers. Many sites require multiple visits with some of the most difficult sites being in the more remote parts of the district.
Cyclone Bola in 1988 was a key event and a “step change” in the erosion problems in the District. The worst eroding or erosion prone land (Land Overlay 3A) must be treated with effective tree cover or fenced for reversion by 2021, according to the Gisborne District Council Combined Regional Land and District Plan. Funding from the Ministry of Primary Industries Erosion Control Funding Project (ECFP) is available to assist landowners in the implementation of Works Plans which detail planting and are prepared in conjunction with Council staff.
EROSION CONTROL FUNDING PROJECT (ECFP)Not all Overlay 3A tree establishment activities made use of the grants and some activities (such as cattle only exclusion on indigenous reversion) are ineligible for funding. ECFP grants are available for tree planting on land outside of Overlay 3A where there are broader erosion control benefits or land identified as “Target Land” under the ECFP. The ECFP is largely used for Overlay 3A activities, so its statistics provide a useful indication of the progress of both projects.
PROGRESS OF OVERLAY 3A WORKS PLAN DEVELOPMENT 2013-2015Year ending 31 Dec No. plans signed/year
O3A area (ha) signed off/year
Total no. of plans signed
Total O3A area (ha) covered by plans
% of total O3A in district covered by plans
2013 27 1,214 170 17,339 37%
2014 47 6,388 217 23,727 51%
2015 17 4,161 234 27,888 60%
SOIL EROSIONGullying and erosion in hill country.
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NEW GRANT APPROVALS (Indicates year of grant approval, not year of establishment)
Year Treatment Total area (ha)
2013
Forestry (all exotic incl P.radiata) 107
Manuka 40
Indigenous reversion 24
Pole planting 340
TOTAL 511
2014
Forestry (all exotic incl P.radiata) 78
Manuka 186
Indigenous reversion 22
Pole planting 92
TOTAL 378
2015
Forestry (all exotic incl P.radiata) 6
Manuka 0
Indigenous reversion 475
Pole planting 255
TOTAL 736
Forestry was once the major component of ECFP grant approvals, however in recent years there is a trend towards increased use of indigenous reversion, and Manuka plantings for honey. This has been particularly in areas more remote from Gisborne Port and follows changes to the funding scheme to better reflect iwi and community aspirations for long term land uses.POPLAR AND WILLOW HARVEST AND PLANTING TALLIES 2013-2015
Source of Poles 2013 2014 2015
Farm/Private nurseries
Poplars 8,150 Poplars 5,260 Poplars 3,755
Willows 2,075 Willows 2,225 Willows 1,075
Warenga-o-kuri nursery (GDC)
Poplars 5,182 Poplars 7,955 Poplars 9,525
Willows 1,405 Willows 1,875 Willows 1,900
TotalsPoplars 13,332 Poplars 13,215 Poplars 13,280
Willows 3,480 Willows 4,100 Willows 2,975
ECFP GRANT APPROVALS
0
100
200
300
400
500
TREATMENT TYPE
Forestry Manuka Indigenous Reversion Pole Planting
AREA
(HEC
TARE
S)
2013 2014 2015
GRANT ACTIVITIES (Established successfully and paid out. Source ECFP GIS Geodatabase)
Year Treatment Total Area (ha) O3A Area (ha) Regional Target
Land (ha)Area by species
Fencing distance (m)
Number of poles
2013
Forestry 671 77 419 P.radiata = 671ha n/a n/a
Indigenous reversion
186 23 86 Native sp. 9,544 n/a
Poles 32 8 8Poplar and
Willown/a 11,769
2014
Forestry 347 93 158 P.radiata = 347ha n/a n/a
Indigenous reversion
10 3 5 Native sp. 774 n/a
Poles 29 15 6Poplar and
Willown/a 8,013
2015
Forestry 77 14 21 P.radiata = 77ha n/a n/a
Indigenous reversion
43 18 25 Native sp. 3,922 n/a
Poles No data n/a n/a n/a n/a n/a
* Data current as of 1 Feb 2016. Areas listed represent what has been paid out for by the ECFP to date not everything that has been established. Some blocks planted in these three years have not yet been paid for due to survival and other issues.
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172,000HECTARES OF FORESTRY IS PLANTED IN THE REGION
PEAK HARVEST AREA OF
7,000HECTARES IN 2013
Much of the forestry was planted as a result of erosion protection schemes, with the rate and amount of plantings accelerating post Cyclone Bola. Many of these forests are now being harvested. Because of erosion issues, all forestry harvest in Gisborne requires a resource consent. Forestry harvest planning tends to be on a two year cycle which is then reflected in consenting activity – with a busy year followed by a less busy year. This trend can be generally observed since 2003, with a step change increase in harvest areas from 2009. However the strongest trend is of the large increase in area of harvest, with a peak being seen of 7000 ha in 2013 when prices were very good. However even the “less busy year” of 2014 saw 6000 ha of forestry harvest consented – five times the area of the “less busy year” of 2003.
May 2015 WHARERATA STORMSoil erosion is often caused by major rain events which either dump a lot of water onto land in a short time or result in extended periods of continual rain. Heavy rainfall causes a lot of runoff which brings stream flows up quickly; causing gully and streambank erosion. Extended rainfall can result in saturated soils that become heavy and lubricated; ideal conditions for slope failure. In some of our steepest hill country when forestry harvest has occurred a “window of vulnerability” of five or so years opens up. Land which was formerly protected from erosion by a tree canopy and root network “lets go” and slips and flows downhill. When woody debris is lying on the slopes after forestry harvest, this gets caught up in landslides and reams out more debris and soil as it moves quickly downhill. This can cause damage to the environment and infrastructure far downstream. The May 2015 Wharerata Storm was a good example of what is becoming a more frequent event in our region as forestry harvest is occurring on steeper slopes – areas often originally planted because of their high erosion risk and tendency to revert to scrub when under a pasture cover. At the time it was often the only land available at a reasonable price for new commercial forestry plantings. Heavy rain fell in an area of the Wharerata Range – at one time at 27.1mm/hour, with 52 mm falling in a two hour period at the Wharerata rain gauge – representing a 1:20 year storm event. This storm resulted in widespread landsliding in forests which had been harvested in the last three years, with sediment and woody debris washing down the Maraetaha and Kopuawhara Streams to the coast. In the Kopuawhara Stream the stopbanked riverbed in the lower reaches around Mahia was filled by woody debris, causing flooding. Large amounts of woody debris from the storm washed up at Orongo south of Young Nick’s Head. Woody debris and sediment was also deposited along the length of the Maraetaha River and its
tributaries – damaging flood gates and blocking culverts on farmland. The issue of how to avoid such events or reduce their impact is something which has been a major focus of a Forestry Environmental Focus Group consisting of major forestry interests in the district. One of the first tools developed has been the slash catcher – which when correctly located, can trap debris which can then be cleared out before the next rain event. The slash catcher is the last line of defence. Management practices to prevent unstable accumulations of logging debris around landings, and to remove larger accumulations from key waterways are also part of the solution. Delayed harvesting of some riparian forest areas, can be beneficial. Work is also underway to develop a Risk Matrix for forestry harvest, so that high risk areas can be identified and more carefully managed. Ultimately this may mean that some locations in the future may be planted in “live” debris catching trees or may not be harvested or after harvest may be left to revert to native forest.
Woody debris blocking the Kopuawhara Stream after May 2015 Wharerata Storm
CASE STUDY
FORESTRY IN GISBORNE
Forestry, planting reducing erosion.
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0
1000
2000
3000
4000
5000
6000
7000
8000
HECT
ARES
YEAR
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
AREA OF CONSENTED FORESTRY HARVEST Year Area of HarvestLength of Roads and
Tracks
2003 1,376ha 107.9km
2004 3,379.4ha 94.9km
2005 398.3ha 48.3km
2006 3,236.4ha 68.1km
2007 957.5ha 29.8km
2008 3,647ha 126.4km
2009 5,002ha 143.5km
2010 2,528ha 73.5km
2011 5,462ha 231km
2012 3,091ha 97km
2013 7,279ha 300km
2014 5,747ha 236km
2015 6,212ha 166km
Currently the forests being harvested are all first rotation forests with associated roading, tracking and landing construction. The Mangatu Forest harvest planning is expected to commence in 2016 and this will be the first of the second rotation forest to be harvested. The earthworks and pre-harvest environmental impacts are expected to be much less in the harvest of second rotation forests.
0
50
100
150
200
250
300
350
KILO
MET
RES
YEAR
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
LENGTH OF CONSENTED FORESTRY ROADS AND TRACKS
Forestry, planting reducing erosion.
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Resource consents were issued to drill two exploratory oil and gas wells in 2012 and 2014. These followed seismic surveys and stratigraphic bores to determine geological structures. Only one exploratory well was drilled, plugged and abandoned. The consultation and publicity around the drilling, and especially potential environmental adverse effects of spills and hydraulic fracturing was considerable.
The Gisborne region is more likely to experience a large earthquake and associated liquefaction than many other areas in New Zealand due to the close proximity of the Hikurangi subduction margin located immediately off the coast. Liquefaction can cause ground surface subsidence due to volumetric densification, the ejection of fluidised sand, topographic re-levelling and lateral spreading, resulting in damage to buildings and infrastructure.In 2015 Council remapped liquefaction vulnerability for the Poverty Bay Flats from Gisborne City inland to Te Karaka. This area is characterised by steep hills surrounding a low lying alluvial plain underlain by soft sediments. The flat land at Sponge Bay to the east of Gisborne also comprises loose alluvial deposits. These geologically young, Holocene deposits are much more likely to liquefy than older more consolidated deposits.Understanding our liquefaction vulnerability will help inform both future planning and development processes.
LIQUEFACTION
Council holds a Hazardous Activities and Industries List (HAIL) database that includes all known city and township sites with the potential for contamination. The list is compiled from Dangerous Goods licensed premises lists, 1990’s list of Potential contaminated sites and information from staff members. The database is not complete and it should be viewed as a list of sites that can be added to and amended. The database does not yet include the many rural farm properties throughout the district. A project to include these rural properties on the database will assist staff when dealing with the many requests
Council keeps an inventory of contaminated sites in the region, and to what extent that they have been remediated. Contaminated sites can include industrial uses like landfills, old petrol station sites, chemical storage and handling areas, gas works and timber treatment sites. In rural areas there can also be contaminated sites associated with chemical use on farms. Strict conditions are put on consents for the excavation and further use of these sites to ensure that any contaminated soil is not transferred to other land therefore creating more contaminated sites. Any soil removed must be taken to a site approved to accept the type of contaminated soil involved. This may involve transporting soil out of the district.
NUMBER AND TYPE OF CONTAMINATED SITES IN REGIONContamination Number Remediated Monitored
Gas Works 1 1
Bulk Fuel Storage Depots 5 5 1
Timber Treatment sites 5 1
Gun Clubs 3
Petrochemical sites 3
566KNOWN HAZARDOUS
ACTIVITY AND INDUSTRY SITES
152 MOTOR VEHICLE
WORKSHOPS ARE THE MAJORITY
under the NES for Assessing and Managing Contaminants in Soil to Protect Human Health and LIM applications.
Council has been liaising with the Ministry of Business Innovation and Enterprise to ascertain how the database held by the ministry on the 42 wells drilled in the Gisborne District since 1874 could be improved. Council staff will be assisting ministry staff to locate as many of these wells as possible and check for for any signs of surface oil and gas leakage greater than that occurring from natural seeps.
CONTAMINATED LAND
LIQUEFACTION VULNERABILITYLow
Medium
High
OIL AND GAS WELLS
LAND HAZARDS