1) Researchers evaluated RFID UHF tags for electronically marking standing trees by testing different tag models attached using screws, staples, or other methods. Tags attached using staples on the underside of bark performed best, with all tags still functioning after one year. 2) The study examined how factors like tag and reader position, moisture content, and dynamic reading influence RFID readability. Distance between tag and reader, moisture content, and angle had significant effects on readability, while tag position on or within the tree also impacted performance. 3) Preliminary results found that moisture content reduction to 40% improved readability by 20%, and tag readability decreased with increasing distance between tag and reader, but

1. FORMEC 2015
Linz 4-7 October
Evaluation of RFID UHF tags for
electronic marking of standing trees
Gianni Picchi
CNR-IVALSA, Italy
Martin Kühmaier
BOKU, Austria
Juan De Dios Diaz
ITENE, Spain

2. The SLOPE project
FORMEC 2015
Linz 4-7 October
Integrated proceSsing and controL systems fOr sustainable forest Production in mountain arEas (SLOPE)
FP7-NMP-2013-SME-7
 10 partners
 3 years
 Precision forestry
 Forest digital model
 Intelligent machines
development

3. Traceability Auto-ID system
FORMEC 2015
Linz 4-7 October
Possible options:
Visual
 barcodes
 QR
 Punching
 Laser marking
 Ink jet data matrix
Electronic
 RFID

4. RFID UHF
FORMEC 2015
Linz 4-7 October
Radio Frequency Identification operating at Ultra High Frequency
LF HF UHF Microwaves
Frequency 125-134 KHz 13.56 MHz 868-902 MHz > 902 MHz
Average
reading range
<1 cm 2-5 cm 0-10m 0-100m
Battery no no no yes

5. Main challenges in forest
FORMEC 2015
Linz 4-7 October
• Capacity to endure long term exposure to forest environment
• Influence of tag and reader position on readability
• Moisture content influence
• Motion influence (dynamic reading)
• Survival rate in forest operations

6. FORMEC 2015
Linz 4-7 October
Marking standing trees
Number Maker Model
1 Omni-ID Exo 600
2 HID Slimflex
3 Confidex Ironside
4 Synometrix SMLM-8200
5 Confidex Ironside Micro
6 Confidex Pino
7 Smartrac Shortdipole
GROUPED ACCORDING TO APPLICATION MODE
1) hard shell - screw or rivet (tags 1,3,4 and 5);
2) soft cover - stapling (tags 2, 6 and 7).
Traditional
system
(axe – stamp)
Stapling
soft cover
Screwing
hard shell

7. Marking and survival analysis
FORMEC 2015
Linz 4-7 October
 Stapling effective and more acceptable than screws
 Under bark position feasible
 After one year all tags operative:
o resin
o tension
o stapling on transponder

8. Materials tag-reader position
FORMEC 2015
Linz 4-7 October
Manual RFID UHF reader CAEN qID R1240I
Windows interface returning value of:
Received Signal Strength Indicator (RSSI)
(negative decibel-milliwatts - dBm)
Smartrac Shortdipole
Freshly felled log
(48% moisture content)

9. FORMEC 2015
Linz 4-7 October
Position of tag and reader
Tag position
Cross cut section
Tangential over bark
Tangential below bark
Distance (cm)
0
10
30
Angle (degrees)
0
30
45
90
180

10. Position of tag and reader
Results
FORMEC 2015
Linz 4-7 October
RSSI
(dBm)
Stnd.
Level Count Mean Error
GRAND MEAN 190 -53.4
Position of tag
1 (on cross cut section) 100 -44.0 2.26
2 (tangential over bark) 40 -58.9 3.94
3 (tangential below bark) 50 -57.3 3.53
Distance (cm)
0 40 -40.3 3.95
10 100 -54.6 2.27
30 50 -65.3 3.61
Angle (°)
0 80 -48.0 2.43
30 40 -51.5 3.82
45 40 -53.6 3.82
180 (through the log) 30 -60.5 4.57
Level
1
2
3
4
Factor Means Plot for RSSI
Vertical scale = -640,0 to -240,0
Angle Distance Position
Angle
Distance
Position
•Distance main factor
• 90° never detectable, 180° just parallel to fiber
• Position significant effect

11. Moisture content
FORMEC 2015
Linz 4-7 October
-60
-55
-50
-45
-40
-35
-30
-25
-20
50% 45% 40% 35% 25% 15% 0%
Readingstrenght(dBm)
Moisture content
Ø 25 cm Ø 35 cm Ø 45 cm
• Clear influence of dielectric effect
• total reduction 37% (minimum -57.8 dBm)
• decreasing moisture to 40% improved RSSI 20%
• superficial moisture apparently most important
• no effect of tree/log size

12. Dynamic reading
FORMEC 2015
Linz 4-7 October
Tag
model
Distance
(cm) Swing
RSSI
main
tag
(dBm) SD
N.
readin
g
RSSI
control
tag
(dBm)
1 100 yes -59.8 1.4 10 0
1 100 no -58.7 1.2 10 0
1 200 yes -64.4 2.2 10 0
1 200 no -63.0 1.3 10 0
1 300 yes -69.2 3.1 10 0
1 300 no 0 0 0 0
1 400 yes 0 0 0 0
1 400 no 0 0 0 0
2 100 yes -55.7 1.9 10 0
2 100 no -53.7 0.7 10 0
2 200 yes -61.0 2.3 10 0
2 200 no -59.7 0.5 10 0
2 300 yes -64.8 1.4 10 0
2 300 no -64.0 1.6 10 0
2 400 yes -66.2 34.9 5 0
2 400 no 0 0 0 0
3 100 yes -66.9 34.6 4 0
3 100 no 0 0 0 0
3 200 yes 0 0 0 0
3 200 no 0 0 0 0
3 300 yes 0 0 0 0
3 300 no 0 0 0 0
3 400 yes 0 0 0 0
3 400 no 0 0 0 0
4 100 yes -65.7 3.3 10 0
4 100 no -68.5 21.7 9 0
4 200 yes 0 0 0 0
4 200 no 0 0 0 0
4 300 yes 0 0 0 0
4 300 no 0 0 0 0
4 400 yes 0 0 0 0
4 400 no 0 0 0 0

13. ThankYou!
FORMEC 2015
Linz 4-7 October
Gianni Picchi - picchi@ivalsa.cnr.it