SEGMENT AND MAJOR CUSTOMER INFORMATION The Partnerships operations are classified into four segments: Partnership Timber, Funds Timber, Timberland Investment Management (TIM), and Real Estate. See Note 2 for a description of the primary activities of each of these segments. Beginning with the first quarter of 2018, we measure segment performance based on Adjusted EBITDDA in addition to operating income. We define Adjusted EBITDDA as earnings, on an internal basis, before interest, taxes, depletion, depreciation, amortization, gain or loss on sales of timberland, and environmental remediation expense. The following tables reconcile internally reported operating income (loss) from operations to Adjusted EBITTDA. In addition, we changed our internal reporting and our segment reporting to segregate our former Fee Timber segment into two segments: Partnership Timber includes the operating results of the Partnerships 100%-owned timberland, while Funds Timber includes the operating results of its three private equity timber funds. Our chief operating decision maker reviews internal financial reporting information at the Partnership Timber and Funds Timber level to allocate resources and evaluate the results of the business. Prior period segment disclosures have been revised to reflect our current segment structure. In 2018, we changed our method of reporting costs incurred by our Partnership Timber segment on behalf of the TIM segment. We reclassified $332,000 and $203,000 of operating expenses in 2017 and 2016 , respectively, from the Partnership Timber segment to the TIM segment to conform to the current year presentation. In the presentation of the Partnerships revenue and operating income (loss) by segment, all inter-segment revenue and expense is eliminated to determine operating income (loss) reported externally. The following tables reconcile internally reported income (loss) from operations to externally reported income (loss) from operations by business segment. For the year ended December 31, 2018 , the Partnership had one customer that represented 13% and another that represented 11% of consolidated revenue. For the year ended December 31, 2017 the Partnership had one customer that represented 12% and another that represented 11% of consolidated revenue. In 2016 , the Partnership had one customers that represented 17% of consolidated revenue. Identifiable assets are those used exclusively in the operations of each reportable segment or those allocated when used jointly. The Partnership does not allocate cash, accounts receivable, certain prepaid expenses, or the cost basis of the Partnerships administrative office for purposes of evaluating segment performance by the chief operating decision maker. Details of the Partnerships operations by business segment for the years ended December 31 are as follows: (in thousands) 2018 Partnership Timber Funds Timber TIM Real Estate Other Consolidated Revenue internal $45,916 $49,819 $4,576 $8,807 $ $109,118 Eliminations (494 )  (4,567 ) (503 ) (5,564 ) Revenue external 45,422 49,819 9 8,304  103,554 Cost of sales (17,828 ) (36,732 )  (3,527 )  (58,087 ) Operating, general and administrative expenses - internal (6,943 ) (9,239 ) (4,566 ) (4,723 ) (7,324 ) (32,795 ) Eliminations 675 4,567 71 144 107 5,564 Operating, general and administrative expenses - external (6,268 ) (4,672 ) (4,495 ) (4,579 ) (7,217 ) (27,231 ) Environmental remediation    (5,600 )  (5,600 ) Income (loss) from operations - internal 21,145 3,848 10 (5,043 ) (7,324 ) 12,636 Eliminations 181 4,567 (4,496 ) (359 ) 107  Income (loss) from operations - external $21,326 $8,415 ($4,486 ) ($5,402 ) ($7,217 ) $12,636 Income (loss) from operations - internal $21,145 $3,848 $10 ($5,043 ) ($7,324 ) $12,636 Depletion, depreciation, and amortization 4,228 23,009 72 270 72 27,651 Environmental remediation    5,600  5,600 Adjusted EBITDDA $25,373 $26,857 $82 $827 ($7,252 ) $45,887 (in thousands) 2017 Partnership Timber Funds Timber TIM Real Estate Other Consolidated Revenue internal $40,004 $33,842 $3,377 $26,737 $ $103,960 Eliminations (332 )  (3,368 ) (437 )  (4,137 ) Revenue external 39,672 33,842 9 26,300  99,823 Cost of sales (14,874 ) (26,910 )  (16,200 )  (57,984 ) Operating, general and administrative expenses - internal (6,177 ) (7,261 ) (3,593 ) (5,594 ) (5,846 ) (28,471 ) Eliminations 506 3,368 73 86 104 4,137 Operating, general and administrative expenses - external (5,671 ) (3,893 ) (3,520 ) (5,508 ) (5,742 ) (24,334 ) Gain (loss) on sale of timberland  12,547    12,547 Income (loss) from operations - internal 18,953 12,218 (216 ) 4,943 (5,846 ) 30,052 Eliminations 174 3,368 (3,295 ) (351 ) 104  Income (loss) from operations - external $19,127 $15,586 ($3,511 ) $4,592 ($5,742 ) $30,052 Income (loss) from operations - internal $18,953 $12,218 ($216 ) $4,943 ($5,846 ) $30,052 Depletion, depreciation, and amortization 4,121 15,170 32 279 55 19,657 Gain on sale of timberland  (12,547 )    (12,547 ) Adjusted EBITDDA $23,074 $14,841 ($184 ) $5,222 ($5,791 ) $37,162 (in thousands) 2016 Partnership Timber Funds Timber TIM Real Estate Other Consolidated Revenue internal $36,478 $21,029 $3,275 $23,419 $ $84,201 Eliminations (203 )  (3,267 ) (303 )  (3,773 ) Revenue external 36,275 21,029 8 23,116  80,428 Cost of sales (15,497 ) (17,145 )  (14,631 )  (47,273 ) Operating, general and administrative expenses - internal (6,152 ) (5,974 ) (2,888 ) (4,441 ) (5,147 ) (24,602 ) Eliminations 331 3,267 57 47 71 3,773 Operating, general and administrative expenses - external (5,821 ) (2,707 ) (2,831 ) (4,394 ) (5,076 ) (20,829 ) Environmental remediation    (7,700 )  (7,700 ) Gain (loss) on sale of timberland 769 226    995 Income (loss) from operations - internal 15,598 (1,864 ) 387 (3,353 ) (5,147 ) 5,621 Eliminations 128 3,267 (3,210 ) (256 ) 71  Income (loss) from operations - external $15,726 $1,403 ($2,823 ) ($3,609 ) ($5,076 ) $5,621 Income (loss) from operations - internal $15,598 ($1,864 ) $387 ($3,353 ) ($5,147 ) $5,621 Depletion, depreciation, and amortization 3,771 9,073 32 387 65 13,328 Environmental remediation    7,700  7,700 Gain on sale of timberland (769 ) (226 )    (995 ) Adjusted EBITDDA $18,600 $6,983 $419 $4,734 ($5,082 ) $25,654 (in thousands) 2018 2017 2016 Depletion, depreciation, and amortization Partnership Timber $ 4,228 $ 4,121 $ 3,771 Funds Timber 23,009 15,170 9,073 Timberland Investment Management 72 32 32 Real Estate 270 279 387 G&amp;A 72 55 65 27,651 19,657 13,328 Amortization of debt issuance costs 74 64 48 Total $ 27,725 $ 19,721 $ 13,376 Assets 2018 2017 2016 Partnership Timber $ 94,353 $ 91,206 $ 87,419 Funds Timber 370,386 244,846 266,401 Timberland Investment Management 211 83 325 Real Estate 36,382 39,420 38,988 G&amp;A 6,917 5,118 5,917 Total $ 508,249 $ 380,673 $ 399,050 Capital and Land Expenditures 2018 2017 2016 Partnership Timber $ 8,186 $ 7,168 $ 40,745 Funds Timber 143,445 6,808 859 Timberland Investment Management 192 32 13 Real Estate project expenditures 3,210 7,588 13,993 Real Estate-other 213 2 128 G&amp;A 65 58 20 Total $ 155,311 $ 21,656 $ 55,758